diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5b9ed230..fa76e1ee 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -109,6 +109,8 @@ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-null-dereference")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-dangling-reference")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wdouble-promotion")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wformat=2")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-system-headers")  # Suppress warnings from external libraries
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-maybe-uninitialized")  # Suppress uninitialized variable warnings from external date library
 
 # Performance optimizations
 if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
diff --git a/docs/changelog.md b/docs/changelog.md
index 5c2042bf..957ef78b 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -61,6 +61,16 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
     - `zone/order_zone.cc` (modified rendering logic)
   - **Impact**: Staff can now easily identify unavailable items, managers can quickly toggle item availability, improves operational efficiency during stock shortages
 
+- **Fixed Order Entry Total Off-by-One-Cent Issue with Tax (2026-01-31)**
+  - Resolved discrepancy between Order Entry zone total display and actual check total when tax is included
+  - **Changes Made**:
+    - Modified OrderEntryZone::Render to use pre-calculated tax totals from SubCheck instead of recalculating tax per individual order
+    - Replaced per-order tax summation with direct use of aggregated tax fields (total_tax_food, total_tax_GST, etc.)
+  - **Root Cause**: Order Entry zone was calculating tax by summing individual order taxes, while check totals use aggregated tax calculation, causing rounding differences
+  - **Solution**: Use the same tax calculation method as the main check total for consistency
+  - **Files modified**: `zone/order_zone.cc` (OrderEntryZone::Render method)
+  - **Impact**: Order Entry zone now displays the exact same total as the final check, eliminating confusion for staff
+
 ### Fixed
 - **Fixed GCC 14 Warning in Date Library (2026-01-25)**
   - Resolved stringop-overflow warning in external/date/include/date/date.h when compiling on Raspberry Pi Compute Module 5 with GCC 14
diff --git a/main/ui/chart.hh b/main/ui/chart.hh
index e8238df0..89b66b2b 100644
--- a/main/ui/chart.hh
+++ b/main/ui/chart.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _CHART_HH
-#define CHART_HH
+#define _CHART_HH
 
 #include "list_utility.hh"
 #include "utility.hh"
diff --git a/term/term_view.cc b/term/term_view.cc
index 636eb50a..ba5e78a3 100644
--- a/term/term_view.cc
+++ b/term/term_view.cc
@@ -1042,7 +1042,7 @@ class IconifyButton : public LO_PushButton
      *code accordingly.  In that case, you should also make the code
      *more dynamic, though it should still be quite fast.
      ****/
-    virtual bool IsPointIn(int px, int py)  // Overrides RegionInfo::IsPointIn but not marked virtual in intermediate classes
+    virtual bool IsPointIn(int px, int py) const noexcept override  // Overrides RegionInfo::IsPointIn but not marked virtual in intermediate classes
         {
             return (px >= (x - EXTRA_ICON_WIDTH)) &&
                 (py >= y) &&
diff --git a/zone/account_zone.hh b/zone/account_zone.hh
index 0b2ef6a1..37bf899d 100644
--- a/zone/account_zone.hh
+++ b/zone/account_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _ACCOUNT_ZONE_HH
-#define ACCOUNT_ZONE_HH
+#define _ACCOUNT_ZONE_HH
 
 #include "form_zone.hh"
 
diff --git a/zone/button_zone.hh b/zone/button_zone.hh
index a9e5e1e0..96925dce 100644
--- a/zone/button_zone.hh
+++ b/zone/button_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _BUTTON_ZONE_HH
-#define BUTTON_ZONE_HH
+#define _BUTTON_ZONE_HH
 
 #include "pos_zone.hh"
 #include "layout_zone.hh"
diff --git a/zone/cdu_zone.hh b/zone/cdu_zone.hh
index a75004e8..189fe1d3 100644
--- a/zone/cdu_zone.hh
+++ b/zone/cdu_zone.hh
@@ -20,7 +20,7 @@
  */
 
 #ifndef _CDU_ZONE_HH
-#define CDU_ZONE_HH
+#define _CDU_ZONE_HH
 
 #include "cdu.hh"
 #include "form_zone.hh"
diff --git a/zone/chart_zone.hh b/zone/chart_zone.hh
index 336b784d..ecd19f67 100644
--- a/zone/chart_zone.hh
+++ b/zone/chart_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _CHART_ZONE_HH
-#define CHART_ZONE_HH
+#define _CHART_ZONE_HH
 
 #include "pos_zone.hh"
 #include "list_utility.hh"
diff --git a/zone/check_list_zone.hh b/zone/check_list_zone.hh
index 11a00ae1..d655beaf 100644
--- a/zone/check_list_zone.hh
+++ b/zone/check_list_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _CHECK_LIST_ZONE_HH
-#define CHECK_LIST_ZONE_HH
+#define _CHECK_LIST_ZONE_HH
 
 #include "form_zone.hh"
 #include "layout_zone.hh"
diff --git a/zone/creditcard_list_zone.hh b/zone/creditcard_list_zone.hh
index 41a10658..5da0186e 100644
--- a/zone/creditcard_list_zone.hh
+++ b/zone/creditcard_list_zone.hh
@@ -18,8 +18,8 @@
  * Touch zone for managing credit cards
  */
 
-#ifndef CREDITCARD_LIST_ZONE_HH
-#define CREDITCARD_LIST_ZONE_HH
+#ifndef _CREDITCARD_LIST_ZONE_HH
+#define _CREDITCARD_LIST_ZONE_HH
 
 #include "form_zone.hh"
 #include "credit.hh"
diff --git a/zone/dialog_zone.hh b/zone/dialog_zone.hh
index c231b724..9351cbb6 100644
--- a/zone/dialog_zone.hh
+++ b/zone/dialog_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _DIALOG_ZONE_HH
-#define DIALOG_ZONE_HH
+#define _DIALOG_ZONE_HH
 
 #include "check.hh"
 #include "layout_zone.hh"
diff --git a/zone/form_zone.hh b/zone/form_zone.hh
index eb4ed578..ae97c314 100644
--- a/zone/form_zone.hh
+++ b/zone/form_zone.hh
@@ -18,8 +18,8 @@
  * base touch zone for data entry and display
  */
 
-#ifndef FORM_ZONE_HH
-#define FORM_ZONE_HH
+#ifndef _FORM_ZONE_HH
+#define _FORM_ZONE_HH
 
 #include "layout_zone.hh"
 #include "report.hh"
diff --git a/zone/inventory_zone.hh b/zone/inventory_zone.hh
index 5d16dcf7..b5935579 100644
--- a/zone/inventory_zone.hh
+++ b/zone/inventory_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _INVENTORY_ZONE_HH
-#define INVENTORY_ZONE_HH
+#define _INVENTORY_ZONE_HH
 
 #include "form_zone.hh"
 
diff --git a/zone/labor_zone.hh b/zone/labor_zone.hh
index 5bd7a42b..3ae27245 100644
--- a/zone/labor_zone.hh
+++ b/zone/labor_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _LABOR_ZONE_HH
-#define LABOR_ZONE_HH
+#define _LABOR_ZONE_HH
 
 #include "form_zone.hh"
 
diff --git a/zone/layout_zone.hh b/zone/layout_zone.hh
index 30fe3d2a..a467e160 100644
--- a/zone/layout_zone.hh
+++ b/zone/layout_zone.hh
@@ -18,8 +18,8 @@
  * base class zone object for display layout
  */
 
-#ifndef LAYOUT_ZONE_HH
-#define LAYOUT_ZONE_HH
+#ifndef _LAYOUT_ZONE_HH
+#define _LAYOUT_ZONE_HH
 
 #include "pos_zone.hh"
 #include "terminal.hh"
diff --git a/zone/login_zone.hh b/zone/login_zone.hh
index 740cfa01..df6847bf 100644
--- a/zone/login_zone.hh
+++ b/zone/login_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _LOGIN_ZONE_HH
-#define LOGIN_ZONE_HH
+#define _LOGIN_ZONE_HH
 
 #include "layout_zone.hh"
 
diff --git a/zone/merchant_zone.hh b/zone/merchant_zone.hh
index 5f6239d1..c064f8b0 100644
--- a/zone/merchant_zone.hh
+++ b/zone/merchant_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _MERCHANT_ZONE_HH
-#define MERCHANT_ZONE_HH
+#define _MERCHANT_ZONE_HH
 
 #include "form_zone.hh"
 
diff --git a/zone/order_zone.cc b/zone/order_zone.cc
index 744c0d62..9d0c31ba 100644
--- a/zone/order_zone.cc
+++ b/zone/order_zone.cc
@@ -244,18 +244,9 @@ RenderResult OrderEntryZone::Render(Terminal *t, int update_flag)
     // Draw Footer
     // Calculate total with tax
     int base_total = sc->raw_sales - sc->item_comps;
-    int total_tax = 0;
-    
-    // Calculate tax for all orders in the subcheck
-    Order *order = sc->OrderList();
-    while (order)
-    {
-        if (!(order->status & ORDER_COMP))
-        {
-            total_tax += order->CalculateTax(s, t);
-        }
-        order = order->next;
-    }
+    int total_tax = sc->total_tax_food + sc->total_tax_alcohol + sc->total_tax_GST +
+                    sc->total_tax_PST + sc->total_tax_HST + sc->total_tax_QST +
+                    sc->total_tax_room + sc->total_tax_merchandise + sc->total_tax_VAT;
     
     int total_with_tax = base_total + total_tax;
     
diff --git a/zone/order_zone.hh b/zone/order_zone.hh
index a3803707..7eee4dec 100644
--- a/zone/order_zone.hh
+++ b/zone/order_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _ORDER_ZONE_HH
-#define ORDER_ZONE_HH
+#define _ORDER_ZONE_HH
 
 #include "layout_zone.hh"
 
diff --git a/zone/payment_zone.hh b/zone/payment_zone.hh
index c9b6ebc5..206f7334 100644
--- a/zone/payment_zone.hh
+++ b/zone/payment_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _PAYMENT_ZONE_HH
-#define PAYMENT_ZONE_HH
+#define _PAYMENT_ZONE_HH
 
 #include "layout_zone.hh"
 #include "check.hh"
diff --git a/zone/payout_zone.hh b/zone/payout_zone.hh
index cee5eff3..75eb98d1 100644
--- a/zone/payout_zone.hh
+++ b/zone/payout_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _PAYOUT_ZONE_HH
-#define PAYOUT_ZONE_HH
+#define _PAYOUT_ZONE_HH
 
 #include "layout_zone.hh"
 
diff --git a/zone/phrase_zone.hh b/zone/phrase_zone.hh
index a5e386d3..a6a1d45e 100644
--- a/zone/phrase_zone.hh
+++ b/zone/phrase_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _PHRASE_ZONE_HH
-#define PHRASE_ZONE_HH
+#define _PHRASE_ZONE_HH
 
 #include "form_zone.hh"
 
diff --git a/zone/pos_zone.hh b/zone/pos_zone.hh
index 1cf1a3a5..10be35d7 100644
--- a/zone/pos_zone.hh
+++ b/zone/pos_zone.hh
@@ -18,8 +18,8 @@
  * Definition of zone types & other zone data
  */
 
-#ifndef POS_ZONE_HH
-#define POS_ZONE_HH
+#ifndef _POS_ZONE_HH
+#define _POS_ZONE_HH
 
 #include "zone.hh"
 
diff --git a/zone/printer_zone.hh b/zone/printer_zone.hh
index 8f6d3ceb..e4c48811 100644
--- a/zone/printer_zone.hh
+++ b/zone/printer_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _PRINTER_ZONE_HH
-#define PRINTER_ZONE_HH
+#define _PRINTER_ZONE_HH
 
 #include "form_zone.hh"
 #include "zone_object.hh"
diff --git a/zone/search_zone.hh b/zone/search_zone.hh
index edffdee9..50a86796 100644
--- a/zone/search_zone.hh
+++ b/zone/search_zone.hh
@@ -18,7 +18,7 @@
  */
 
 #ifndef _SEARCH_ZONE_HH
-#define SEARCH_ZONE_HH
+#define _SEARCH_ZONE_HH
 
 #include "layout_zone.hh"
 
diff --git a/zone/settings_zone.hh b/zone/settings_zone.hh
index 07ac3942..f86f4a0f 100644
--- a/zone/settings_zone.hh
+++ b/zone/settings_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _SETTINGS_ZONE_H
-#define SETTINGS_ZONE_H
+#define _SETTINGS_ZONE_H
 
 #include "form_zone.hh"
 
diff --git a/zone/split_check_zone.hh b/zone/split_check_zone.hh
index 7243e5e0..c6c538f6 100644
--- a/zone/split_check_zone.hh
+++ b/zone/split_check_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _SPLIT_CHECK_HH
-#define SPLIT_CHECK_HH
+#define _SPLIT_CHECK_HH
 
 #include "pos_zone.hh"
 #include "zone_object.hh"
diff --git a/zone/table_zone.hh b/zone/table_zone.hh
index 112bcc23..1dd45a8a 100644
--- a/zone/table_zone.hh
+++ b/zone/table_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _TABLE_ZONE_HH
-#define TABLE_ZONE_HH
+#define _TABLE_ZONE_HH
 
 #include "check.hh"
 #include "customer.hh"
diff --git a/zone/user_edit_zone.hh b/zone/user_edit_zone.hh
index aa696b99..29d60799 100644
--- a/zone/user_edit_zone.hh
+++ b/zone/user_edit_zone.hh
@@ -19,7 +19,7 @@
  */
 
 #ifndef _USER_EDIT_ZONE_HH
-#define USER_EDIT_ZONE_HH
+#define _USER_EDIT_ZONE_HH
 
 #include "form_zone.hh"
 
diff --git a/zone/video_zone.hh b/zone/video_zone.hh
index 4f9adcc5..f6e8958c 100644
--- a/zone/video_zone.hh
+++ b/zone/video_zone.hh
@@ -19,6 +19,9 @@
  *  to determine which food types get sent to the Kitchen Video reports.
  */
 
+#ifndef _VIDEO_ZONE_HH
+#define _VIDEO_ZONE_HH
+
 #define VIDEO_TARGET_NORMAL  0
 #define VIDEO_TARGET_KITCHEN 1
 
@@ -40,3 +43,5 @@ public:
     int LoadRecord(Terminal *t, int record) override;
     int SaveRecord(Terminal *t, int record, int write_file) override;
 };
+
+#endif
diff --git a/zone/zone.hh b/zone/zone.hh
index 40ac00ae..bbd6b280 100644
--- a/zone/zone.hh
+++ b/zone/zone.hh
@@ -6,8 +6,8 @@
  * Functions for managing zones on a view
  */
 
-#ifndef ZONE_HH
-#define ZONE_HH
+#ifndef _ZONE_HH
+#define _ZONE_HH
 
 #include "utility.hh"
 #include "list_utility.hh"
diff --git a/zone/zone_object.hh b/zone/zone_object.hh
index dcd16c84..7c5f239b 100644
--- a/zone/zone_object.hh
+++ b/zone/zone_object.hh
@@ -18,8 +18,8 @@
  * User Interfact componet objects
  */
 
-#ifndef ZONE_OBJECT_HH
-#define ZONE_OBJECT_HH
+#ifndef _ZONE_OBJECT_HH
+#define _ZONE_OBJECT_HH
 
 #include "utility.hh"
 #include "list_utility.hh"