diff --git a/src/frontend/src/lib/insight/groups.ts b/src/frontend/src/lib/insight/groups.ts
index d06335dae..d0800828b 100644
--- a/src/frontend/src/lib/insight/groups.ts
+++ b/src/frontend/src/lib/insight/groups.ts
@@ -136,7 +136,10 @@ const AI_ADOPTION_COLLECTION: MetricCollectionConfig = {
     { key: "ai.active_days", views: [{ view: "period" }, { view: "peer" }] },
     { key: "ai.cost", views: [{ view: "period" }, { view: "peer" }] },
     {
-      key: "ai.extra_usage_cost",
+      // The daily distribution, not the month's running total: this section
+      // reads a metric one day at a time, and a cumulative figure repeated on
+      // every day of the month is not a day's reading.
+      key: "ai.daily_approximate_extra_usage_cost",
       views: [{ view: "period" }, { view: "peer" }],
     },
     {
@@ -472,7 +475,7 @@ export const GROUPS: readonly MetricGroup[] = [
       preview: [
         "ai.active_days",
         "ai.cost",
-        "ai.extra_usage_cost",
+        "ai.daily_approximate_extra_usage_cost",
         "ai.accepted_lines",
       ],
     },
diff --git a/src/frontend/src/lib/portal/overview-configs.ts b/src/frontend/src/lib/portal/overview-configs.ts
index 37e83119f..13b811c40 100644
--- a/src/frontend/src/lib/portal/overview-configs.ts
+++ b/src/frontend/src/lib/portal/overview-configs.ts
@@ -31,7 +31,9 @@ export const OVERVIEW_ITEMS: Record<string, LensConfig> = {
           "tasks.closed",
           "collab.messages_sent",
           "ai.cost",
-          "ai.extra_usage_cost",
+          // The daily distribution: this row totals a period, and only the
+          // per-day steps add up to one. The month's running snapshot does not.
+          "ai.daily_approximate_extra_usage_cost",
         ],
       },
       // The old header's "N using AI" stat, now an honest participation card