diff --git a/open-sse/services/combo.js b/open-sse/services/combo.js
index b3bb9930..1f134f3c 100644
--- a/open-sse/services/combo.js
+++ b/open-sse/services/combo.js
@@ -43,47 +43,54 @@ export async function handleComboChat({ body, models, handleSingleModel, log })
     const modelStr = models[i];
     log.info("COMBO", `Trying model ${i + 1}/${models.length}: ${modelStr}`);
 
-    const result = await handleSingleModel(body, modelStr);
-    
-    // Success (2xx) - return response
-    if (result.ok) {
-      log.info("COMBO", `Model ${modelStr} succeeded`);
-      return result;
-    }
-
-    // Extract error info from response
-    let errorText = result.statusText || "";
-    let retryAfter = null;
     try {
-      const errorBody = await result.clone().json();
-      errorText = errorBody?.error?.message || errorBody?.error || errorBody?.message || errorText;
-      retryAfter = errorBody?.retryAfter || null;
-    } catch {
-      // Ignore JSON parse errors
-    }
+      const result = await handleSingleModel(body, modelStr);
+      
+      // Success (2xx) - return response
+      if (result.ok) {
+        log.info("COMBO", `Model ${modelStr} succeeded`);
+        return result;
+      }
 
-    // Track earliest retryAfter across all combo models
-    if (retryAfter && (!earliestRetryAfter || new Date(retryAfter) < new Date(earliestRetryAfter))) {
-      earliestRetryAfter = retryAfter;
-    }
+      // Extract error info from response
+      let errorText = result.statusText || "";
+      let retryAfter = null;
+      try {
+        const errorBody = await result.clone().json();
+        errorText = errorBody?.error?.message || errorBody?.error || errorBody?.message || errorText;
+        retryAfter = errorBody?.retryAfter || null;
+      } catch {
+        // Ignore JSON parse errors
+      }
 
-    // Normalize error text to string (Worker-safe)
-    if (typeof errorText !== "string") {
-      try { errorText = JSON.stringify(errorText); } catch { errorText = String(errorText); }
-    }
+      // Track earliest retryAfter across all combo models
+      if (retryAfter && (!earliestRetryAfter || new Date(retryAfter) < new Date(earliestRetryAfter))) {
+        earliestRetryAfter = retryAfter;
+      }
 
-    // Check if should fallback to next model
-    const { shouldFallback } = checkFallbackError(result.status, errorText);
-    
-    if (!shouldFallback) {
-      log.warn("COMBO", `Model ${modelStr} failed (no fallback)`, { status: result.status });
-      return result;
-    }
+      // Normalize error text to string (Worker-safe)
+      if (typeof errorText !== "string") {
+        try { errorText = JSON.stringify(errorText); } catch { errorText = String(errorText); }
+      }
 
-    // Fallback to next model
-    lastError = errorText || String(result.status);
-    if (!lastStatus) lastStatus = result.status;
-    log.warn("COMBO", `Model ${modelStr} failed, trying next`, { status: result.status });
+      // Check if should fallback to next model
+      const { shouldFallback } = checkFallbackError(result.status, errorText);
+      
+      if (!shouldFallback) {
+        log.warn("COMBO", `Model ${modelStr} failed (no fallback)`, { status: result.status });
+        return result;
+      }
+
+      // Fallback to next model
+      lastError = errorText || String(result.status);
+      if (!lastStatus) lastStatus = result.status;
+      log.warn("COMBO", `Model ${modelStr} failed, trying next`, { status: result.status });
+    } catch (error) {
+      // Catch unexpected exceptions to ensure fallback continues
+      lastError = error.message || String(error);
+      if (!lastStatus) lastStatus = 500;
+      log.warn("COMBO", `Model ${modelStr} threw error, trying next`, { error: lastError });
+    }
   }
 
   // All models failed
diff --git a/src/app/(dashboard)/dashboard/usage/components/OverviewCards.js b/src/app/(dashboard)/dashboard/usage/components/OverviewCards.js
index 6d88f6b1..59925b12 100644
--- a/src/app/(dashboard)/dashboard/usage/components/OverviewCards.js
+++ b/src/app/(dashboard)/dashboard/usage/components/OverviewCards.js
@@ -22,8 +22,9 @@ export default function OverviewCards({ stats }) {
         <span className="text-2xl font-bold text-success">{fmt(stats.totalCompletionTokens)}</span>
       </Card>
       <Card className="px-4 py-3 flex flex-col gap-1">
-        <span className="text-text-muted text-sm uppercase font-semibold">Total Cost</span>
-        <span className="text-2xl font-bold text-warning">{fmtCost(stats.totalCost)}</span>
+        <span className="text-text-muted text-sm uppercase font-semibold">Est. Cost</span>
+        <span className="text-2xl font-bold text-warning">~{fmtCost(stats.totalCost)}</span>
+        <span className="text-[10px] text-text-muted">Estimated, not actual billing</span>
       </Card>
     </div>
   );
diff --git a/src/app/(dashboard)/dashboard/usage/components/ProviderTopology.js b/src/app/(dashboard)/dashboard/usage/components/ProviderTopology.js
index eaf810da..42b08154 100644
--- a/src/app/(dashboard)/dashboard/usage/components/ProviderTopology.js
+++ b/src/app/(dashboard)/dashboard/usage/components/ProviderTopology.js
@@ -1,11 +1,13 @@
 "use client";
 
-import { useMemo, useState } from "react";
+import { useMemo, useState, useCallback, useRef, useEffect } from "react";
 import PropTypes from "prop-types";
 import {
   ReactFlow,
   Handle,
   Position,
+  useNodesState,
+  useEdgesState,
 } from "@xyflow/react";
 import "@xyflow/react/dist/style.css";
 import { AI_PROVIDERS } from "@/shared/constants/providers";
@@ -206,11 +208,36 @@ export default function ProviderTopology({ providers = [], activeRequests = [],
     [errorProvider]
   );
 
-  const { nodes: initialNodes, edges: initialEdges } = useMemo(
+  // Stable key for providers list — only changes when provider set changes
+  const providersKey = useMemo(
+    () => providers.map((p) => p.provider).sort().join(","),
+    [providers]
+  );
+
+  const { nodes: layoutNodes, edges: layoutEdges } = useMemo(
     () => buildLayout(providers, activeSet, lastSet, errorSet),
     [providers, activeSet, lastSet, errorSet]
   );
 
+  const [nodes, setNodes, onNodesChange] = useNodesState(layoutNodes);
+  const [edges, setEdges, onEdgesChange] = useEdgesState(layoutEdges);
+  const rfInstance = useRef(null);
+
+  // Sync nodes/edges when data changes
+  useEffect(() => {
+    setNodes(layoutNodes);
+    setEdges(layoutEdges);
+    // Re-fit view after update
+    if (rfInstance.current) {
+      setTimeout(() => rfInstance.current.fitView({ padding: 0.3 }), 50);
+    }
+  }, [layoutNodes, layoutEdges, setNodes, setEdges]);
+
+  const onInit = useCallback((instance) => {
+    rfInstance.current = instance;
+    setTimeout(() => instance.fitView({ padding: 0.3 }), 50);
+  }, []);
+
   return (
     <div className="w-full rounded-lg border border-border bg-bg-subtle/30" style={{ height: 480 }}>
       {providers.length === 0 ? (
@@ -219,12 +246,15 @@ export default function ProviderTopology({ providers = [], activeRequests = [],
         </div>
       ) : (
         <ReactFlow
-          nodes={initialNodes}
-          edges={initialEdges}
+          key={providersKey}
+          nodes={nodes}
+          edges={edges}
+          onNodesChange={onNodesChange}
+          onEdgesChange={onEdgesChange}
           nodeTypes={nodeTypes}
           fitView
           fitViewOptions={{ padding: 0.3 }}
-          onInit={(instance) => setTimeout(() => instance.fitView({ padding: 0.3 }), 50)}
+          onInit={onInit}
           proOptions={{ hideAttribution: true }}
           panOnDrag={false}
           zoomOnScroll={false}