diff --git a/tpl/macro.twig b/tpl/macro.twig
index e0cbce8..04560bd 100644
--- a/tpl/macro.twig
+++ b/tpl/macro.twig
@@ -1,4 +1,3 @@
-
 {% macro decl_units(meta) %}
 
 {%- for u in meta.getunits ~%}
@@ -17,7 +16,7 @@
 
 {% endmacro %}
 
-{% macro decl_struct(o, extra = '') %}
+{% macro decl_struct(o, allow_diffs = true, extra = '') %}
 
 {% set pkey_fields = token(o, 'table_pkey')|split(',') %}
 {% set pkey = o.fields|filter(f => f.name in pkey_fields ) %}
@@ -111,7 +110,7 @@ public {{_self.struct_type(o)}} {{o.name}} {{_self.base_struct_class(o)}}
   }
 {%- endif -%}
 
-{%- if has_token(o, 'diffable') ~%}
+{%- if has_token(o, 'diffable') and allow_diffs ~%}
   {{_self.diffable_support(o)}}
 {%- endif -%}
 
@@ -378,8 +377,12 @@ public class {{o.name}} : IRpc
      return !no_changes;
     }
     
+    {% set unique_diff_units = [] %}
     {% for u in get_diff_related_units(o) %}
-    {{_self.diff_methods_for(u)}}
+      {% if u not in unique_diff_units %}
+        {{_self.diff_methods_for(u)}}
+        {% set unique_diff_units = unique_diff_units|merge([u]) %}
+      {% endif %}
     {% endfor %}
 
 {% endmacro %}