diff --git a/csrc/libtorch_stable/layernorm_kernels.cu b/csrc/libtorch_stable/layernorm_kernels.cu
index eb121b0b88..f29734fc26 100644
--- a/csrc/libtorch_stable/layernorm_kernels.cu
+++ b/csrc/libtorch_stable/layernorm_kernels.cu
@@ -81,11 +81,11 @@ __global__ void rms_norm_kernel(
 #pragma unroll
     for (int j = 0; j < VEC_SIZE; j++) {
       float x = static_cast<float>(src1.val[j]);
-      scalar_t normalized = static_cast<scalar_t>(x * s_variance);
       if constexpr (HasWeight) {
-        dst.val[j] = normalized * src2.val[j];
+        float w = static_cast<float>(src2.val[j]);
+        dst.val[j] = static_cast<scalar_t>(x * s_variance * w);
       } else {
-        dst.val[j] = normalized;
+        dst.val[j] = static_cast<scalar_t>(x * s_variance);
       }
     }
     v_out[i] = dst;
@@ -151,7 +151,8 @@ fused_add_rms_norm_kernel(
 #pragma unroll
       for (int j = 0; j < width; ++j) {
         float x = Converter::convert(res.data[j]);
-        out.data[j] = Converter::convert(x * s_variance) * w.data[j];
+        float wf = Converter::convert(w.data[j]);
+        out.data[j] = Converter::convert(x * s_variance * wf);
       }
     } else {
 #pragma unroll
@@ -198,8 +199,8 @@ fused_add_rms_norm_kernel(
   for (int idx = threadIdx.x; idx < hidden_size; idx += blockDim.x) {
     float x = (float)residual[blockIdx.x * hidden_size + idx];
     if constexpr (HasWeight) {
-      input[blockIdx.x * input_stride + idx] =
-          (scalar_t)(x * s_variance) * weight[idx];
+      float w = (float)weight[idx];
+      input[blockIdx.x * input_stride + idx] = (scalar_t)(x * s_variance * w);
     } else {
       input[blockIdx.x * input_stride + idx] = (scalar_t)(x * s_variance);
     }
diff --git a/csrc/libtorch_stable/layernorm_quant_kernels.cu b/csrc/libtorch_stable/layernorm_quant_kernels.cu
index 32f3495f4e..26ffa76d6e 100644
--- a/csrc/libtorch_stable/layernorm_quant_kernels.cu
+++ b/csrc/libtorch_stable/layernorm_quant_kernels.cu
@@ -66,8 +66,13 @@ __global__ void rms_norm_static_fp8_quant_kernel(
 #pragma unroll
     for (int j = 0; j < VEC_SIZE; j++) {
       float x = static_cast<float>(src1.val[j]);
-      // Multiply in weight's native dtype to match rms_norm_kernel.
-      scalar_t out_norm = static_cast<scalar_t>(x * s_variance) * src2.val[j];
+      float w = static_cast<float>(src2.val[j]);
+      // Round normalized result through scalar_t to match the precision of the
+      // unfused composite (rms_norm writes scalar_t, then
+      // static_scaled_fp8_quant re-loads it as float before FP8 conversion).
+      // Without this round, the fused path is strictly more accurate and
+      // disagrees with the composite at exact E4M3 quantization tie boundaries.
+      scalar_t out_norm = static_cast<scalar_t>(x * s_variance * w);
       out[blockIdx.x * hidden_size + idx * VEC_SIZE + j] =
           scaled_fp8_conversion<true, fp8_type>(static_cast<float>(out_norm),
                                                 scale_inv);
@@ -137,8 +142,12 @@ fused_add_rms_norm_static_fp8_quant_kernel(
 #pragma unroll
     for (int i = 0; i < width; ++i) {
       float x = Converter::convert(res.data[i]);
-      // Multiply in weight's native dtype to match fused_add_rms_norm_kernel.
-      HipT out_norm_h = Converter::convert(x * s_variance) * w.data[i];
+      float wf = Converter::convert(w.data[i]);
+      // See note in rms_norm_static_fp8_quant_kernel: round through scalar_t
+      // to match the unfused composite path at FP8 boundaries. We use the
+      // backend's hip_type for the intermediate since c10::Half/BFloat16 has
+      // ambiguous conversions on CUDA and no implicit conversion on ROCm.
+      HipT out_norm_h = Converter::convert(x * s_variance * wf);
       out[id * width + i] = scaled_fp8_conversion<true, fp8_type>(
           Converter::convert(out_norm_h), scale_inv);
     }
@@ -183,8 +192,10 @@ fused_add_rms_norm_static_fp8_quant_kernel(
 
   for (int idx = threadIdx.x; idx < hidden_size; idx += blockDim.x) {
     float x = (float)residual[blockIdx.x * hidden_size + idx];
-    // Multiply in weight's native dtype to match fused_add_rms_norm_kernel.
-    scalar_t out_norm = static_cast<scalar_t>(x * s_variance) * weight[idx];
+    float w = (float)weight[idx];
+    // See note in rms_norm_static_fp8_quant_kernel: round through scalar_t
+    // to match the unfused composite path at FP8 boundaries.
+    scalar_t out_norm = static_cast<scalar_t>(x * s_variance * w);
     out[blockIdx.x * hidden_size + idx] = scaled_fp8_conversion<true, fp8_type>(
         static_cast<float>(out_norm), scale_inv);
   }