diff --git a/nnef/src/registry.rs b/nnef/src/registry.rs
index d4dd4c8653..3b7f819f6f 100644
--- a/nnef/src/registry.rs
+++ b/nnef/src/registry.rs
@@ -220,9 +220,13 @@ impl Registry {
 
             // mitigation of nnef "scalar" type mismatch with tract-core more
             // strict types
-            if (!a_dt.is_quantized() || !b_dt.is_quantized()) && a_dt != b_dt {
-                let operating_dt = if a_dt == TDim::datum_type() || b_dt == TDim::datum_type() {
-                    TDim::datum_type()
+            if !a_dt.is_quantized() || !b_dt.is_quantized() {
+                let operating_dt = if a_dt == b_dt
+                    && bin.1.operating_datum_type(a_dt, b_dt).map(|it| it == a_dt).unwrap_or(false)
+                {
+                    a_dt
+                } else if a_dt == TDim::datum_type() || b_dt == TDim::datum_type() {
+                    bin.1.operating_datum_type(a_dt, b_dt)?
                 } else if builder.model.node(a.node).op_is::<tract_core::ops::konst::Const>() {
                     b_dt
                 } else if builder.model.node(b.node).op_is::<tract_core::ops::konst::Const>() {
@@ -230,11 +234,10 @@ impl Registry {
                 } else {
                     bin.1.operating_datum_type(a_dt, b_dt)?
                 };
-                // avoid cast unified dtype to happen when all inputs quantized
-                // that can be unaligned at process time
                 a = builder.wire_as_outlets(tract_core::ops::cast::cast(operating_dt), &[a])?[0];
                 b = builder.wire_as_outlets(tract_core::ops::cast::cast(operating_dt), &[b])?[0];
             }
+
             let inputs = multi_rank_broadcast(builder, &[a, b])?;
 
             let c_dt: Option<DatumType> = dt.first().cloned().and_then(|dt| dt);