diff --git a/src/dvsim/flow/one_shot.py b/src/dvsim/flow/one_shot.py
index c717eea2..4505b867 100644
--- a/src/dvsim/flow/one_shot.py
+++ b/src/dvsim/flow/one_shot.py
@@ -171,13 +171,32 @@ def gen_results(self, results: Sequence[CompletedJobStatus]) -> None:
         for item in self.cfgs:
             project = item.name
 
+            # We want to report all the results with the correct block
+            # (checking the name) and also with the correct variant.
+            #
+            # For the latter check, we don't necessarily know that item (the
+            # configuration that is being run) is a type that defines variant
+            # at all. If not, we just interpret the variant as None.
+            item_variant = getattr(item, "variant", None)
+
+            # The typing of the configuration also doesn't guarantee it has a
+            # _gen_results function, which we will need here. Check that it
+            # really exists: if not, we'll have to fail at runtime.
+            gen_results_fun = getattr(item, "_gen_results", None)
+            if not gen_results_fun:
+                msg = (
+                    f"Cannot generate results for FlowCfg {item.name}: "
+                    "not an instance of a class that defines _gen_results"
+                )
+                raise RuntimeError(msg)
+
             item_results = [
                 res
                 for res in results
-                if res.block.name == item.name and res.block.variant == item.variant
+                if res.block.name == item.name and res.block.variant == item_variant
             ]
 
-            result = item._gen_results(item_results)
+            result = gen_results_fun(item_results)
 
             log.info("[results]: [%s]:\n%s\n", project, result)
             log.info("[scratch_path]: [%s] [%s]", project, item.scratch_path)