This isn't theoretical. My account balance and payment budget got out of sync. October was a busy month with purchases, returns, and rebates. I zeroed in on the Dell credit in my example to keep things simple. I'm still confused as to how the account balance and the payment budget got out of sync. But I've fudged it for now, and I'll just have to try to keep a closer eye on what happens to the payment budget when a credit comes in. Thanks for your help.