diff --git a/tests/e2e/coverage_registry/llm_conversational.yaml b/tests/e2e/coverage_registry/llm_conversational.yaml
index 61f3be34a43..919884b66f0 100644
--- a/tests/e2e/coverage_registry/llm_conversational.yaml
+++ b/tests/e2e/coverage_registry/llm_conversational.yaml
@@ -101,10 +101,10 @@
 - {id: llm.messages.together_ai.basic.stream.works, module: llm, tier: P1, subject_endpoint: messages, route: together_ai, capability: basic, streaming: stream, assertions: [works], source: "llm_translation/test_together_ai_e2e.py", rationale: "Together over /v1/messages streaming"}
 - {id: llm.messages.together_ai.tool_use.nonstream.works, module: llm, tier: P1, subject_endpoint: messages, route: together_ai, capability: tool_use, streaming: nonstream, assertions: [works], source: "llm_translation/test_together_ai_e2e.py", rationale: "Together tool calls over /v1/messages"}
 - {id: llm.messages.together_ai.multi_turn.nonstream.works, module: llm, tier: P1, subject_endpoint: messages, route: together_ai, capability: multi_turn, streaming: nonstream, assertions: [works], source: "llm_translation/test_together_ai_e2e.py", rationale: "Together tool result round trip over /v1/messages"}
-- {id: llm.chat_completions.sail.service_tier.nonstream.cost_logged, module: llm, tier: P1, subject_endpoint: chat_completions, route: sail, capability: service_tier, streaming: nonstream, assertions: [cost_logged], source: "llm_translation/test_sail_e2e.py", rationale: "service_tier flex, balanced and auto map to Sail completion windows and bill the matching price columns"}
+- {id: llm.chat_completions.sail.service_tier.nonstream.cost_logged, module: llm, tier: P1, subject_endpoint: chat_completions, route: sail, capability: service_tier, streaming: nonstream, assertions: [cost_logged], source: "llm_translation/test_sail_e2e.py", rationale: "service_tier balanced and auto map to Sail completion windows and bill the matching price columns; Sail serves flex only to background responses and Batch"}
 - {id: llm.chat_completions.sail.service_tier.nonstream.rejects_unknown_tier, module: llm, tier: P1, subject_endpoint: chat_completions, route: sail, capability: service_tier, streaming: nonstream, assertions: [rejects_unknown_tier], source: "llm_translation/test_sail_e2e.py", rationale: "A service_tier Sail has no completion window for is a 400 without drop_params"}
 - {id: llm.chat_completions.sail.service_tier.nonstream.drops_unknown_tier_and_bills_asap, module: llm, tier: P1, subject_endpoint: chat_completions, route: sail, capability: service_tier, streaming: nonstream, assertions: [drops_unknown_tier_and_bills_asap], source: "llm_translation/test_sail_e2e.py", rationale: "An unknown service_tier under drop_params is dropped and billed at asap in both the cost header and spend log"}
-- {id: llm.responses.sail.service_tier.nonstream.cost_logged, module: llm, tier: P1, subject_endpoint: responses, route: sail, capability: service_tier, streaming: nonstream, assertions: [cost_logged], source: "llm_translation/test_sail_e2e.py", rationale: "A caller metadata.completion_window of flex on /v1/responses bills Sail flex rates"}
+- {id: llm.responses.sail.service_tier.nonstream.cost_logged, module: llm, tier: P1, subject_endpoint: responses, route: sail, capability: service_tier, streaming: nonstream, assertions: [cost_logged], source: "llm_translation/test_sail_e2e.py", rationale: "A caller metadata.completion_window of balanced on /v1/responses bills Sail balanced rates"}
 - {id: llm.messages.sail.basic.nonstream.works, module: llm, tier: P1, subject_endpoint: messages, route: sail, capability: basic, streaming: nonstream, assertions: [works], source: "llm_translation/test_sail_e2e.py", rationale: "Sail over /v1/messages"}
 - {id: llm.chat_completions.anthropic.basic.nonstream.cost_logged, module: llm, tier: P0, subject_endpoint: chat_completions, route: anthropic, capability: basic, streaming: nonstream, assertions: [works, cost_logged], source: "llm_translation/test_conversational_matrix_e2e.py", rationale: "Anthropic over /chat/completions: cost header and spend row agree"}
 - {id: llm.chat_completions.anthropic.multi_turn.nonstream.works, module: llm, tier: P0, subject_endpoint: chat_completions, route: anthropic, capability: multi_turn, streaming: nonstream, assertions: [works], source: "llm_translation/test_conversational_matrix_e2e.py", rationale: "Anthropic tool result round trip over /chat/completions"}
diff --git a/tests/e2e/llm_translation/test_sail_e2e.py b/tests/e2e/llm_translation/test_sail_e2e.py
index cf662afea90..7267052e12c 100644
--- a/tests/e2e/llm_translation/test_sail_e2e.py
+++ b/tests/e2e/llm_translation/test_sail_e2e.py
@@ -117,7 +117,7 @@ def _assert_spend_row_matches(proxy: ProxyClient, key: str, header_cost: float)
 class TestSailChatCompletions:
     @pytest.mark.covers("llm.chat_completions.sail.service_tier.nonstream.cost_logged")
     @pytest.mark.parametrize(
-        ("service_tier", "billed_tier"), [("flex", "flex"), ("balanced", "balanced"), ("auto", "base")]
+        ("service_tier", "billed_tier"), [("balanced", "balanced"), ("auto", "base")]
     )
     def test_service_tier_bills_the_matching_completion_window(
         self,
@@ -176,7 +176,7 @@ class TestSailChatCompletions:
 
 class TestSailResponses:
     @pytest.mark.covers("llm.responses.sail.service_tier.nonstream.cost_logged")
-    def test_flex_completion_window_bills_flex_rates(
+    def test_caller_completion_window_bills_its_rates(
         self, proxy: ProxyClient, resources: ResourceManager, sdk: SdkClients
     ) -> None:
         model, key = _register(proxy, resources)
@@ -185,7 +185,7 @@ class TestSailResponses:
             model=model,
             input=f"{PROMPT} {unique_marker()}",
             max_output_tokens=MAX_TOKENS,
-            metadata={"completion_window": "flex"},
+            metadata={"completion_window": "balanced"},
             extra_body=NO_PROXY_CACHE,
         )
         usage: Final = raw.parse().usage
@@ -196,7 +196,9 @@ class TestSailResponses:
             completion=usage.output_tokens,
         )
 
-        header_cost: Final = _assert_billed_at("flex", tokens, response_header(raw.headers, "x-litellm-response-cost"))
+        header_cost: Final = _assert_billed_at(
+            "balanced", tokens, response_header(raw.headers, "x-litellm-response-cost")
+        )
         _assert_spend_row_matches(proxy, key, header_cost)