diff --git a/tools/compare_fl2va_free_run.py b/tools/compare_fl2va_free_run.py
index bd82de5..ef39a5f 100644
--- a/tools/compare_fl2va_free_run.py
+++ b/tools/compare_fl2va_free_run.py
@@ -7,7 +7,7 @@ import torch
 from h3_blackwell_runtime.checkpoint import H3Checkpoint
 from h3_blackwell_runtime.denoiser import H3PackedDenoiser
 from h3_blackwell_runtime.packing import H3PromptPacker, unpatchify_video
-from h3_blackwell_runtime.sampler import _audio_sigma, _unpack_audio, res_multistep_update
+from h3_blackwell_runtime.sampler import _audio_sigma, _model_sigma, _unpack_audio, res_multistep_update
 from h3_blackwell_runtime.t2v import random_av_latents
 
 
@@ -51,7 +51,7 @@ for index, sigma in enumerate(sigmas[:-1]):
         text,
         video,
         audio_carried.to(torch.bfloat16) * carry,
-        float(sigma),
+        _model_sigma(sigma),
         model_timesteps,
     )
     hidden_delta = (hidden.float() - h3_input["hidden"].to("cuda").float()).abs()