diff --git a/comfy/model_base.py b/comfy/model_base.py
index cc278a770..970c56e37 100644
--- a/comfy/model_base.py
+++ b/comfy/model_base.py
@@ -1507,23 +1507,8 @@ class WAN21_SCAIL(WAN21):
             pose_latents = torch.cat([pose_latents, pose_mask], dim=1)
             out['pose_latents'] = comfy.conds.CONDRegular(pose_latents)
 
-        pose_start = kwargs.get("pose_start", 0.0)
-        pose_end = kwargs.get("pose_end", 1.0)
-        out['pose_start'] = comfy.conds.CONDConstant(pose_start)
-        out['pose_end'] = comfy.conds.CONDConstant(pose_end)
-
         return out
 
-    def apply_model(self, x, t, c_concat=None, c_crossattn=None, control=None, transformer_options={}, pose_start=0.0, pose_end=1.0, **kwargs):
-        if t[0] >= self.model_sampling.percent_to_sigma(pose_start) or t[0] <= self.model_sampling.percent_to_sigma(pose_end):
-            kwargs.pop("pose_latents", None)
-
-        return comfy.patcher_extension.WrapperExecutor.new_class_executor(
-            self._apply_model,
-            self,
-            comfy.patcher_extension.get_all_wrappers(comfy.patcher_extension.WrappersMP.APPLY_MODEL, transformer_options)
-        ).execute(x, t, c_concat, c_crossattn, control, transformer_options, **kwargs)
-
     def extra_conds_shapes(self, **kwargs):
         out = {}
         ref_latents = kwargs.get("reference_latents", None)
diff --git a/comfy_extras/nodes_wan.py b/comfy_extras/nodes_wan.py
index 9e7aab3e3..e50bfcd2c 100644
--- a/comfy_extras/nodes_wan.py
+++ b/comfy_extras/nodes_wan.py
@@ -1505,8 +1505,8 @@ class WanSCAILToVideo(io.ComfyNode):
         if pose_video is not None:
             pose_video = comfy.utils.common_upscale(pose_video[:length].movedim(-1, 1), width // 2, height // 2, "area", "center").movedim(1, -1)
             pose_video_latent = vae.encode(pose_video[:, :, :, :3]) * pose_strength
-            positive = node_helpers.conditioning_set_values(positive, {"pose_video_latent": pose_video_latent, "pose_start": pose_start, "pose_end": pose_end})
-            negative = node_helpers.conditioning_set_values(negative, {"pose_video_latent": pose_video_latent, "pose_start": pose_start, "pose_end": pose_end})
+            positive = node_helpers.conditioning_set_values_with_timestep_range(positive, {"pose_video_latent": pose_video_latent}, pose_start, pose_end)
+            negative = node_helpers.conditioning_set_values_with_timestep_range(negative, {"pose_video_latent": pose_video_latent}, pose_start, pose_end)
 
         out_latent = {}
         out_latent["samples"] = latent
diff --git a/node_helpers.py b/node_helpers.py
index 4ff960ef8..d3d834516 100644
--- a/node_helpers.py
+++ b/node_helpers.py
@@ -1,5 +1,6 @@
 import hashlib
 import torch
+import logging
 
 from comfy.cli_args import args
 
@@ -21,6 +22,36 @@ def conditioning_set_values(conditioning, values={}, append=False):
 
     return c
 
+def conditioning_set_values_with_timestep_range(conditioning, values={}, start_percent=0.0, end_percent=1.0):
+    """
+    Apply values to conditioning only during [start_percent, end_percent], keeping the
+    original conditioning active outside that range. Respects existing per-entry ranges.
+    """
+    if start_percent > end_percent:
+        logging.warning(f"start_percent ({start_percent}) must be <= end_percent ({end_percent})")
+        return conditioning
+
+    EPS = 1e-5 # the sampler gates entries with strict > / <, shift boundaries slightly to ensure only one conditioning is active per timestep
+    c = []
+    for t in conditioning:
+        cond_start = t[1].get("start_percent", 0.0)
+        cond_end   = t[1].get("end_percent",   1.0)
+        intersect_start = max(start_percent, cond_start)
+        intersect_end   = min(end_percent,   cond_end)
+
+        if intersect_start >= intersect_end: # no overlap: emit unchanged
+            c.append(t)
+            continue
+
+        if intersect_start > cond_start: # part before the requested range
+            c.extend(conditioning_set_values([t], {"start_percent": cond_start, "end_percent": intersect_start - EPS}))
+
+        c.extend(conditioning_set_values([t], {**values, "start_percent": intersect_start, "end_percent": intersect_end}))
+
+        if intersect_end < cond_end: # part after the requested range
+            c.extend(conditioning_set_values([t], {"start_percent": intersect_end + EPS, "end_percent": cond_end}))
+    return c
+
 def pillow(fn, arg):
     prev_value = None
     try: