diff --git a/internal/collector/scrape_test.go b/internal/collector/scrape_test.go
index 641e6706..4c70e4cc 100644
--- a/internal/collector/scrape_test.go
+++ b/internal/collector/scrape_test.go
@@ -636,12 +636,12 @@ func Test_TopologyScrapes(t *testing.T) {
 	)
 
 	// set some quota acpq values.
-	// resource level
-	_, err := s.DB.Exec(`UPDATE project_resources SET quota = $1 WHERE name = $2`, 20, "capacity")
+	// resource level (ACPQ always writes 0 on this level for AZSeparatedResourceTopology)
+	_, err := s.DB.Exec(`UPDATE project_resources SET quota = NULL WHERE name = $1`, "capacity")
 	if err != nil {
 		t.Fatal(err)
 	}
-	_, err = s.DB.Exec(`UPDATE project_resources SET quota = $1 WHERE name = $2`, 13, "things")
+	_, err = s.DB.Exec(`UPDATE project_resources SET quota = NULL WHERE name = $1`, "things")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -668,10 +668,10 @@ func Test_TopologyScrapes(t *testing.T) {
 		UPDATE project_az_resources SET backend_quota = 13 WHERE id = 7 AND resource_id = 3 AND az = 'az-two';
 		UPDATE project_az_resources SET backend_quota = 20 WHERE id = 8 AND resource_id = 4 AND az = 'az-one';
 		UPDATE project_az_resources SET backend_quota = 20 WHERE id = 9 AND resource_id = 4 AND az = 'az-two';
-		UPDATE project_resources SET backend_quota = 20 WHERE id = 1 AND service_id = 1 AND name = 'capacity';
-		UPDATE project_resources SET backend_quota = 13 WHERE id = 3 AND service_id = 1 AND name = 'things';
-		UPDATE project_resources SET backend_quota = 20 WHERE id = 4 AND service_id = 2 AND name = 'capacity';
-		UPDATE project_resources SET backend_quota = 13 WHERE id = 6 AND service_id = 2 AND name = 'things';
+		UPDATE project_resources SET backend_quota = NULL WHERE id = 1 AND service_id = 1 AND name = 'capacity';
+		UPDATE project_resources SET backend_quota = NULL WHERE id = 3 AND service_id = 1 AND name = 'things';
+		UPDATE project_resources SET backend_quota = NULL WHERE id = 4 AND service_id = 2 AND name = 'capacity';
+		UPDATE project_resources SET backend_quota = NULL WHERE id = 6 AND service_id = 2 AND name = 'things';
 		UPDATE project_services SET quota_desynced_at = NULL, quota_sync_duration_secs = 5 WHERE id = 1 AND project_id = 1 AND type = 'unittest';
 		UPDATE project_services SET quota_desynced_at = NULL, quota_sync_duration_secs = 5 WHERE id = 2 AND project_id = 2 AND type = 'unittest';
 	`)
@@ -696,8 +696,12 @@ func Test_TopologyScrapes(t *testing.T) {
 		UPDATE project_az_resources SET backend_quota = NULL WHERE id = 7 AND resource_id = 3 AND az = 'az-two';
 		UPDATE project_az_resources SET backend_quota = 50 WHERE id = 8 AND resource_id = 4 AND az = 'az-one';
 		UPDATE project_az_resources SET backend_quota = 50 WHERE id = 9 AND resource_id = 4 AND az = 'az-two';
-		UPDATE project_services SET scraped_at = %[1]d, checked_at = %[1]d, next_scrape_at = %[2]d WHERE id = 1 AND project_id = 1 AND type = 'unittest';
-		UPDATE project_services SET scraped_at = %[3]d, checked_at = %[3]d, next_scrape_at = %[4]d WHERE id = 2 AND project_id = 2 AND type = 'unittest';
+		UPDATE project_resources SET quota = 0, backend_quota = 40 WHERE id = 1 AND service_id = 1 AND name = 'capacity';
+		UPDATE project_resources SET quota = 0, backend_quota = 26 WHERE id = 3 AND service_id = 1 AND name = 'things';
+		UPDATE project_resources SET quota = 0, backend_quota = 40 WHERE id = 4 AND service_id = 2 AND name = 'capacity';
+		UPDATE project_resources SET quota = 0, backend_quota = 26 WHERE id = 6 AND service_id = 2 AND name = 'things';
+		UPDATE project_services SET scraped_at = %[1]d, checked_at = %[1]d, next_scrape_at = %[2]d, quota_desynced_at = %[1]d WHERE id = 1 AND project_id = 1 AND type = 'unittest';
+		UPDATE project_services SET scraped_at = %[3]d, checked_at = %[3]d, next_scrape_at = %[4]d, quota_desynced_at = %[3]d WHERE id = 2 AND project_id = 2 AND type = 'unittest';
 	`,
 		checkedAt1.Unix(), checkedAt1.Add(scrapeInterval).Unix(),
 		checkedAt2.Unix(), checkedAt2.Add(scrapeInterval).Unix(),
diff --git a/internal/collector/sync_quota_to_backend.go b/internal/collector/sync_quota_to_backend.go
index d7e32589..0c0f3fdf 100644
--- a/internal/collector/sync_quota_to_backend.go
+++ b/internal/collector/sync_quota_to_backend.go
@@ -93,10 +93,12 @@ func (c *Collector) processQuotaSyncTask(ctx context.Context, srv db.ProjectServ
 }
 
 var (
+	// NOTE: This query does not use `AND quota IS NOT NULL` to filter out NoQuota resources
+	// because it would also filter out resources with AZSeparatedResourceTopology.
 	quotaSyncSelectQuery = sqlext.SimplifyWhitespace(`
 		SELECT id, name, backend_quota, quota
 		  FROM project_resources
-		 WHERE service_id = $1 AND quota IS NOT NULL
+		 WHERE service_id = $1
 	`)
 	azQuotaSyncSelectQuery = sqlext.SimplifyWhitespace(`
 		SELECT az, backend_quota, quota
@@ -140,17 +142,23 @@ func (c *Collector) performQuotaSync(ctx context.Context, srv db.ProjectService,
 	var azSeparatedResourceIDs []db.ProjectResourceID
 	err := sqlext.ForeachRow(c.DB, quotaSyncSelectQuery, []any{srv.ID}, func(rows *sql.Rows) error {
 		var (
-			resourceID   db.ProjectResourceID
-			resourceName liquid.ResourceName
-			currentQuota *int64
-			targetQuota  uint64
+			resourceID     db.ProjectResourceID
+			resourceName   liquid.ResourceName
+			currentQuota   *int64
+			targetQuotaPtr *uint64
 		)
-		err := rows.Scan(&resourceID, &resourceName, &currentQuota, &targetQuota)
+		err := rows.Scan(&resourceID, &resourceName, &currentQuota, &targetQuotaPtr)
 		if err != nil {
 			return err
 		}
+		logg.Info("looking at: resourceID = %d", resourceID)
 
 		resInfo := c.Cluster.InfoForResource(srv.Type, resourceName)
+		if !resInfo.HasQuota {
+			return nil
+		}
+
+		var targetQuota uint64
 		if resInfo.Topology == liquid.AZSeparatedResourceTopology {
 			// for AZSeparatedResourceTopology, project_resources.quota is effectively empty (always set to zero)
 			// and `targetQuota` needs to be computed by summing over project_az_resources.quota
@@ -176,6 +184,7 @@ func (c *Collector) performQuotaSync(ctx context.Context, srv db.ProjectService,
 				targetAZQuotasInDB[resourceName][availabilityZone] = liquid.AZResourceQuotaRequest{Quota: targetAZQuota}
 				targetQuota += targetAZQuota
 				if currentAZQuota == nil || *currentAZQuota < 0 || uint64(*currentAZQuota) != targetAZQuota {
+					logg.Info("need to apply AZ: resourceID = %d, az = %s: %v -> %d", resourceID, availabilityZone, currentAZQuota, targetAZQuota)
 					azSeparatedNeedsApply = true
 				}
 				return nil
@@ -183,10 +192,17 @@ func (c *Collector) performQuotaSync(ctx context.Context, srv db.ProjectService,
 			if err != nil {
 				return err
 			}
+		} else {
+			// for anything except AZSeparatedResourceTopology, the total target quota is just what we have in project_resources.quota
+			if targetQuotaPtr == nil {
+				return fmt.Errorf("found unexpected NULL value in project_resources.quota for id = %d", resourceID)
+			}
+			targetQuota = *targetQuotaPtr
 		}
 
 		targetQuotasInDB[resourceName] = targetQuota
 		if currentQuota == nil || *currentQuota < 0 || uint64(*currentQuota) != targetQuota {
+			logg.Info("need to apply proj: resourceID = %d: %v -> %d", resourceID, currentQuota, targetQuota)
 			needsApply = true
 		}
 		return nil
diff --git a/internal/datamodel/apply_computed_project_quota.go b/internal/datamodel/apply_computed_project_quota.go
index d8003431..6c683b7d 100644
--- a/internal/datamodel/apply_computed_project_quota.go
+++ b/internal/datamodel/apply_computed_project_quota.go
@@ -201,14 +201,17 @@ func ApplyComputedProjectQuota(serviceType db.ServiceType, resourceName liquid.R
 	}
 
 	err = sqlext.WithPreparedStatement(tx, acpqUpdateProjectQuotaQuery, func(stmt *sql.Stmt) error {
-		// Skip resources with AZSeparatedResourceTopology. The quota scrape would receive a resource nil value, while ACPQ calculates qouta.
-		// This would lead to unnecessary quota syncs with the backend, because backendQuota != quota.
-		if resInfo.Topology == liquid.AZSeparatedResourceTopology {
-			return nil
-		}
 		for resourceID, quota := range quotasByResourceID {
+			// Resources with AZSeparatedResourceTopology will report `backendQuota == nil` during scrape.
+			// If we set anything other than nil here, this would lead to unnecessary quota syncs with the backend,
+			// because backendQuota != quota.
+			quotaToWrite := &quota
+			if resInfo.Topology == liquid.AZSeparatedResourceTopology {
+				quotaToWrite = nil
+			}
+
 			var serviceID db.ProjectServiceID
-			err := stmt.QueryRow(quota, resourceID).Scan(&serviceID)
+			err := stmt.QueryRow(quotaToWrite, resourceID).Scan(&serviceID)
 			if err == sql.ErrNoRows {
 				// if quota was not actually changed, do not remember this project service as being stale
 				continue