diff --git a/ethosu/vela/graph_optimiser_util.py b/ethosu/vela/graph_optimiser_util.py
index 73fbf6c..3e15f12 100644
--- a/ethosu/vela/graph_optimiser_util.py
+++ b/ethosu/vela/graph_optimiser_util.py
@@ -49,15 +49,18 @@
 
 def _avoid_nhcwb16_for_split(tens):
     # If read offset is not a multiple of 16 in the C-dimension, NHCWB16 need to be avoided in the input
+
+    # Return True if NHCWB16 needs to be avoided
+    def offset_not_aligned(read_offset):
+        return read_offset is not None and (read_offset.depth % 16) != 0
+
     for cons_op in tens.consumer_list:
         if cons_op.ifm == tens:
-            read_offset = cons_op.read_offsets[0]
-        elif cons_op.type.is_binary_elementwise_op() and cons_op.ifm2 == tens:
-            read_offset = cons_op.read_offsets[1]
-        else:
-            assert False
-        if read_offset is not None and (read_offset[-1] % 16) != 0:
-            return True
+            if offset_not_aligned(cons_op.read_offsets[0]):
+                return True
+        if cons_op.ifm2 is not None and cons_op.ifm2 == tens:
+            if offset_not_aligned(cons_op.read_offsets[1]):
+                return True
     return False