diff --git a/crates/benilla-app/src/addon_harness/tick_bench_tests.rs b/crates/benilla-app/src/addon_harness/tick_bench_tests.rs
index ba9b4d67..648f4bee 100644
--- a/crates/benilla-app/src/addon_harness/tick_bench_tests.rs
+++ b/crates/benilla-app/src/addon_harness/tick_bench_tests.rs
@@ -1252,6 +1252,23 @@ fn hover_frame(s: &mut UiScript, company: Company, plates: &[PlateFeed], rebuild
 /// text (0.1 requests a frame, the same held or rebuilt): neither the patch chain nor the font
 /// engine is in this cost, so neither can explain the part of grom's 90-to-31 fps that the VM
 /// does not account for. Whatever the rest is, it is app-side, outside this harness.
+///
+/// **What the derive tally and the frame count add** (both printed per window): a rebuild gives up
+/// naming the layout graph exactly **once each**, always at `model.rs`'s `frame_id` — which is the
+/// mint of a frame the model has not seen before, and the one write that genuinely cannot be named
+/// precisely, since a new node has to join the cached graph. A held hover does not.
+///
+/// The frame is not ours. `OctoPawn` hangs an `OnShow` on `GameTooltip` and, on every show,
+/// creates an anonymous `CreateFrame("Frame")` purely to own a one-shot `OnUpdate` delay — twice,
+/// from `Scoring/ScoringCore.lua:540` and `UI/Paperdoll/Pdmo.lua:101`, which is the ordinary 1.12
+/// way to write `C_Timer.After`. So **every** tooltip raise on his interface mints frames and
+/// therefore re-derives, on the reference client too. The live frame count rises by far less than
+/// the number created (137 against 480 here), so Lua reclaims most of them; it is a cost per
+/// raise, not an unbounded leak.
+///
+/// Kept as instrumentation rather than acted on: the lever would be letting a brand-new leaf node
+/// join the graph without a full derive, which is a layout-engine change and wants its own
+/// measurement.
 #[test]
 #[ignore = "bench — needs WOW_DATA and the player's AddOns; run explicitly with --release"]
 fn a_mouseover_plate_rebuilt_every_frame() {
@@ -1273,6 +1290,7 @@ fn a_mouseover_plate_rebuilt_every_frame() {
         font_us: 0.0,
     });
     install_live_asset_probes(&mut s, &data, &root, &PROBES);
+    let _ = s.take_layout_derive_sites(); // the first take is what arms the tally
     let plates = plate_feeds();
     let per = f64::from(FRAMES);
 
@@ -1327,6 +1345,17 @@ fn a_mouseover_plate_rebuilt_every_frame() {
                 (after.2 - before.2) as f64 / per,
                 (after.3 - before.3) / per / 1000.0,
             );
+            for (site, n) in s.take_layout_derive_sites().iter().take(5) {
+                println!("[hover] {shape} {label}   {n:5} derives from {site}");
+            }
+            println!(
+                "[hover] {shape} {label}   counts {:?}",
+                s.tick_profile_counts()
+                    .iter()
+                    .filter(|(l, _)| *l == "frames" || *l == "regions")
+                    .map(|(l, n)| format!("{l} {n:.0}"))
+                    .collect::<Vec<_>>()
+            );
             let errs = s.take_errors();
             if !errs.is_empty() {
                 println!(