diff --git a/modules/mesh-mail-reader/cmd/mesh-mail-reader/batch.go b/modules/mesh-mail-reader/cmd/mesh-mail-reader/batch.go
index 8f0a801b..99693fa4 100644
--- a/modules/mesh-mail-reader/cmd/mesh-mail-reader/batch.go
+++ b/modules/mesh-mail-reader/cmd/mesh-mail-reader/batch.go
@@ -283,20 +283,24 @@ func RunOneBatch(ctx context.Context, store Store, readText ReadTextFunc, judge
 	return recordOutcome(ctx, store, OutcomeOK, "", judgedAt)
 }
 
-// RunBatches is the loop the running module drives (main.go): pace batch starts at least BatchGap apart
+// RunBatches is the loop the running module drives (main.go): pace batch starts at least gap apart
 // (nextBatchWait), take at most MaxMailsPerBatch of the waiting mails in arrival order, run one batch at a
 // time, and after each one — win or lose — try the mail signal (SendSignal, tell.go, issue 1522; it is its
 // own no-op when there is nothing untold that matters, or the reader is unhealthy) — forever, until ctx is
-// done. Not unit-tested itself beyond compiling (go vet): 1520/AC1's pacing and AC2-AC5's one-batch
-// behaviour, and 1522's signal-sending, are each proven directly, on nextBatchWait, RunOneBatch and
-// SendSignal, in batch_test.go and tell_test.go.
-func RunBatches(ctx context.Context, store Store, readText ReadTextFunc, judge JudgeFunc, check MessengerCheck, tell Tell, now func() time.Time, sleep func(time.Duration), logf func(string, ...any)) {
+// done. gap is given explicitly (main.go's batchLoop passes the var BatchGap, which only a `-tags
+// integration` build ever shortens; TestThirtyWaitingMailsRunAsThreeBatchesAtLeast160sApart passes
+// MinBatchGap) so this function itself never reads that var — the try on 8000b637 found this test still
+// reading it (and so, compiled into the integration binary, pacing at the shortened 3s instead of 160s)
+// when RunBatches read BatchGap directly inside its own loop (review round 2, issue 1520). 1520/AC2-AC5's
+// one-batch behaviour and 1522's signal-sending are proven directly, on RunOneBatch and SendSignal, in
+// batch_test.go and tell_test.go.
+func RunBatches(ctx context.Context, store Store, readText ReadTextFunc, judge JudgeFunc, check MessengerCheck, tell Tell, now func() time.Time, sleep func(time.Duration), logf func(string, ...any), gap time.Duration) {
 	var lastStart time.Time
 	for {
 		if ctx.Err() != nil {
 			return
 		}
-		if wait := nextBatchWait(lastStart, now(), BatchGap); wait > 0 {
+		if wait := nextBatchWait(lastStart, now(), gap); wait > 0 {
 			sleep(wait)
 			continue
 		}
diff --git a/modules/mesh-mail-reader/cmd/mesh-mail-reader/batch_test.go b/modules/mesh-mail-reader/cmd/mesh-mail-reader/batch_test.go
index 2403babd..c882125b 100644
--- a/modules/mesh-mail-reader/cmd/mesh-mail-reader/batch_test.go
+++ b/modules/mesh-mail-reader/cmd/mesh-mail-reader/batch_test.go
@@ -122,7 +122,7 @@ func TestThirtyWaitingMailsRunAsThreeBatchesAtLeast160sApart(t *testing.T) {
 
 	done := make(chan struct{})
 	go func() {
-		RunBatches(ctx, store, noopReadText, judge, check, tell, now, sleep, noopLogf)
+		RunBatches(ctx, store, noopReadText, judge, check, tell, now, sleep, noopLogf, MinBatchGap)
 		close(done)
 	}()
 	select {
diff --git a/modules/mesh-mail-reader/cmd/mesh-mail-reader/catchup_integration_test.go b/modules/mesh-mail-reader/cmd/mesh-mail-reader/catchup_integration_test.go
index a45480cb..b81cb62b 100644
--- a/modules/mesh-mail-reader/cmd/mesh-mail-reader/catchup_integration_test.go
+++ b/modules/mesh-mail-reader/cmd/mesh-mail-reader/catchup_integration_test.go
@@ -128,10 +128,14 @@ func TestAcceptanceRefusedJudgementIsUnhealthyThenCatchesUpInPublishedOrder(t *t
 	if !sinceRE.MatchString(why) {
 		t.Fatalf("health's why = %q, want it to name since when (HH:MM YYYY-MM-DD, health.go's own Answer)", why)
 	}
-	before := tellCalls.get()
+	// Exactly 1 (the dropped tell of the healthy phase, above) — never a relative "unchanged since some
+	// point after unhealthy was already seen", which a tell sent in the SAME loop pass that made the
+	// reader unhealthy would already be baked into (review round 2, issue 1524): waitFor's own poll above
+	// only reads health, so a wrongly-sent tell from that very batch would predate this read and hide
+	// behind it.
 	time.Sleep(2 * time.Second) // give the next failed batch attempt, if any, time to run and fail again
-	if n := tellCalls.get(); n != before {
-		t.Fatalf("a tell was sent while unhealthy: %d call(s), want still %d (the untold mail from above)", n, before)
+	if n := tellCalls.get(); n != 1 {
+		t.Fatalf("tellCalls = %d, want exactly 1 (the dropped tell from the healthy phase; none while unhealthy)", n)
 	}
 
 	// The judge answers again (1524/AC2): catch-up in the order the two mails were published.
diff --git a/modules/mesh-mail-reader/cmd/mesh-mail-reader/main.go b/modules/mesh-mail-reader/cmd/mesh-mail-reader/main.go
index 2478127e..e85b95a2 100644
--- a/modules/mesh-mail-reader/cmd/mesh-mail-reader/main.go
+++ b/modules/mesh-mail-reader/cmd/mesh-mail-reader/main.go
@@ -100,7 +100,7 @@ func batchLoop(storeFor func(context.Context) (Store, error)) {
 	judge := NewJudge(bundleAsk, node, time.Now)
 	check := NewMessengerCheck(bundleAsk)
 	tell := NewTell(bundleAsk)
-	RunBatches(context.Background(), store, readText, judge, check, tell, time.Now, time.Sleep, logf)
+	RunBatches(context.Background(), store, readText, judge, check, tell, time.Now, time.Sleep, logf, BatchGap)
 }
 
 // ---- hearing --------------------------------------------------------------------------------------------------