diff --git a/modules/EcommerceFinance/Repositories/SmallPaymentWorkOrderMirrorRepository.php b/modules/EcommerceFinance/Repositories/SmallPaymentWorkOrderMirrorRepository.php
index f5b6e80c..27e307ed 100644
--- a/modules/EcommerceFinance/Repositories/SmallPaymentWorkOrderMirrorRepository.php
+++ b/modules/EcommerceFinance/Repositories/SmallPaymentWorkOrderMirrorRepository.php
@@ -211,6 +211,9 @@ class SmallPaymentWorkOrderMirrorRepository
                 $join->on('work_order_versions.woNo', '=', 'p.woNo');
             })
             ->join($workOrders . ' AS w', 'w.Id', '=', 'work_order_versions.Id')
+            // Match the leading columns of (woTypeId, woNo, Id), rather than
+            // rescanning all orders of this type for every payment-map row.
+            ->whereColumn('w.woNo', 'p.woNo')
             ->where('p.woTypeId', self::SMALL_PAYMENT_WORK_TYPE_ID)
             ->where('w.woTypeId', self::SMALL_PAYMENT_WORK_TYPE_ID);
     }