diff --git a/metricflow/dataflow/builder/dataflow_plan_builder.py b/metricflow/dataflow/builder/dataflow_plan_builder.py
index ec7cf59c1..db251c37e 100644
--- a/metricflow/dataflow/builder/dataflow_plan_builder.py
+++ b/metricflow/dataflow/builder/dataflow_plan_builder.py
@@ -1938,35 +1938,34 @@ def _build_custom_offset_time_spine_node(
         time_spine_source = self._choose_time_spine_source((DataSet.metric_time_dimension_spec(custom_grain),))
         time_spine_read_node = self._choose_time_spine_read_node(time_spine_source)
         if {spec.time_granularity for spec in required_time_spine_specs} == {custom_grain}:
-            # If querying with only the same grain as is used in the offset_window, can use a simpler plan.
-            raise NotImplementedError("Support for offset windows with custom granularities is still in progress.")
-        else:
-            # For custom offset windows queried with other granularities, first, build CustomGranularityBoundsNode.
-            # This will be used twice in the output node, and ideally will be turned into a CTE.
-            bounds_node = CustomGranularityBoundsNode.create(
-                parent_node=time_spine_read_node, custom_granularity_name=custom_grain.name
-            )
-            # Build a FilterElementsNode from bounds node to get required unique rows.
-            bounds_data_set = self._node_data_set_resolver.get_output_data_set(bounds_node)
-            bounds_specs = tuple(
-                bounds_data_set.instance_from_window_function(window_func).spec
-                for window_func in (SqlWindowFunction.FIRST_VALUE, SqlWindowFunction.LAST_VALUE)
-            )
-            custom_grain_spec = bounds_data_set.instance_from_time_dimension_grain_and_date_part(
-                time_granularity_name=custom_grain.name, date_part=None
-            ).spec
-            filter_elements_node = FilterElementsNode.create(
-                parent_node=bounds_node,
-                include_specs=InstanceSpecSet(time_dimension_specs=(custom_grain_spec,) + bounds_specs),
-                distinct=True,
-            )
-            # Pass both the CustomGranularityBoundsNode and the FilterElementsNode into the OffsetByCustomGranularityNode.
-            return OffsetByCustomGranularityNode.create(
-                custom_granularity_bounds_node=bounds_node,
-                filter_elements_node=filter_elements_node,
-                offset_window=offset_window,
-                required_time_spine_specs=required_time_spine_specs,
-            )
+            # TODO: If querying with only the same grain as is used in the offset_window, can use a simpler plan.
+            pass
+        # For custom offset windows queried with other granularities, first, build CustomGranularityBoundsNode.
+        # This will be used twice in the output node, and ideally will be turned into a CTE.
+        bounds_node = CustomGranularityBoundsNode.create(
+            parent_node=time_spine_read_node, custom_granularity_name=custom_grain.name
+        )
+        # Build a FilterElementsNode from bounds node to get required unique rows.
+        bounds_data_set = self._node_data_set_resolver.get_output_data_set(bounds_node)
+        bounds_specs = tuple(
+            bounds_data_set.instance_from_window_function(window_func).spec
+            for window_func in (SqlWindowFunction.FIRST_VALUE, SqlWindowFunction.LAST_VALUE)
+        )
+        custom_grain_spec = bounds_data_set.instance_from_time_dimension_grain_and_date_part(
+            time_granularity_name=custom_grain.name, date_part=None
+        ).spec
+        filter_elements_node = FilterElementsNode.create(
+            parent_node=bounds_node,
+            include_specs=InstanceSpecSet(time_dimension_specs=(custom_grain_spec,) + bounds_specs),
+            distinct=True,
+        )
+        # Pass both the CustomGranularityBoundsNode and the FilterElementsNode into the OffsetByCustomGranularityNode.
+        return OffsetByCustomGranularityNode.create(
+            custom_granularity_bounds_node=bounds_node,
+            filter_elements_node=filter_elements_node,
+            offset_window=offset_window,
+            required_time_spine_specs=required_time_spine_specs,
+        )
 
     def _sort_by_base_granularity(self, time_dimension_specs: Sequence[TimeDimensionSpec]) -> List[TimeDimensionSpec]:
         """Sort the time dimensions by their base granularity.