diff --git a/lib/WebGUI/Shop/Cart.pm b/lib/WebGUI/Shop/Cart.pm
index e6ce6201d..043033128 100644
--- a/lib/WebGUI/Shop/Cart.pm
+++ b/lib/WebGUI/Shop/Cart.pm
@@ -911,6 +911,8 @@ sub www_update {
         }
         if ($self->readyForCheckout()) {
             my $total = $self->calculateTotal;
+            ##Handle rounding errors, and checkout immediately if the amount is 0 since
+            ##at least the ITransact driver won't accept $0 checkout.
             if (sprintf('%.2f', $total + $self->calculateShopCreditDeduction($total)) eq '0.00') {
                 my $transaction = WebGUI::Shop::Transaction->create($session, {self => $self});
                 $transaction->completePurchase('zero', 'success', 'success');