diff --git a/litellm/cost_calculator.py b/litellm/cost_calculator.py
index a17c40b3438..36f561e2553 100644
--- a/litellm/cost_calculator.py
+++ b/litellm/cost_calculator.py
@@ -1757,11 +1757,13 @@ def completion_cost(
                         custom_llm_provider = (
                             candidate_pricing_provider
                             or pricing_provider
-                            or hidden_params.get("custom_llm_provider")
-                            or candidate_custom_llm_provider
+                            or hidden_params.get(
+                                "custom_llm_provider",
+                                candidate_custom_llm_provider or custom_llm_provider or None,
+                            )
                         )
                         region_name = hidden_params.get("region_name", region_name)
-                    else:
+                    elif candidate_pricing_provider or candidate_custom_llm_provider:
                         custom_llm_provider = candidate_pricing_provider or candidate_custom_llm_provider
 
                 else:
diff --git a/litellm/llms/openai_like/chat/transformation.py b/litellm/llms/openai_like/chat/transformation.py
index 23a47db9947..5a7bd809e4d 100644
--- a/litellm/llms/openai_like/chat/transformation.py
+++ b/litellm/llms/openai_like/chat/transformation.py
@@ -153,11 +153,11 @@ class OpenAILikeChatConfig(OpenAIGPTConfig):
         resolved_custom_llm_provider = (
             litellm_params.get("custom_llm_provider") if isinstance(litellm_params, dict) else None
         ) or (
-            getattr(model_response, "_hidden_params", {}).get("custom_llm_provider")
-            if hasattr(model_response, "_hidden_params") and isinstance(getattr(model_response, "_hidden_params"), dict)
+            model_response._hidden_params.get("custom_llm_provider")
+            if isinstance(model_response._hidden_params, dict)
             else None
         )
-        return OpenAILikeChatConfig._transform_response(
+        transformed_response = OpenAILikeChatConfig._transform_response(
             model=model,
             response=raw_response,
             model_response=model_response,
@@ -170,9 +170,18 @@ class OpenAILikeChatConfig(OpenAIGPTConfig):
             print_verbose=None,
             encoding=None,
             json_mode=json_mode,
-            custom_llm_provider=resolved_custom_llm_provider,
+            custom_llm_provider=None,
             base_model=None,
         )
+        if resolved_custom_llm_provider is not None and isinstance(transformed_response._hidden_params, dict):
+            transformed_response._hidden_params.setdefault("custom_llm_provider", resolved_custom_llm_provider)
+            if (
+                transformed_response.model
+                and "/" in transformed_response.model
+                and not transformed_response.model.startswith(f"{resolved_custom_llm_provider}/")
+            ):
+                transformed_response.model = f"{resolved_custom_llm_provider}/{transformed_response.model}"
+        return transformed_response
 
     def map_openai_params(
         self,