diff --git a/openmc/dagmc.py b/openmc/dagmc.py
index 016d30cb625..3652e677fdf 100644
--- a/openmc/dagmc.py
+++ b/openmc/dagmc.py
@@ -118,7 +118,10 @@ def material_overrides(self):
 
     @material_overrides.setter
     def material_overrides(self, val):
-        if val is not None:
+        if val is None:
+            self._material_overrides = val
+            return
+        else:
             cv.check_type('material overrides', val, dict)
             for key, value in val.items():
                 # ensuring key is a string and exists in the DAGMC file
diff --git a/openmc/model/model.py b/openmc/model/model.py
index 39272b563e7..065f6eebd1b 100644
--- a/openmc/model/model.py
+++ b/openmc/model/model.py
@@ -1072,7 +1072,7 @@ def differentiate_mats(self, diff_volume_method: str = None, depletable_only: bo
         # Extract all depletable materials which have multiple instances
         distribmats = set(
             [mat for mat in self.materials
-                if mat.depletable and mat.num_instances > 1])
+                if (mat.depletable or depletable_only) and mat.num_instances > 1])
 
         if diff_volume_method == "divide equally":
             for mat in distribmats: