Did you get to the invoice screen, Jim?
Yep; all the way through, clicked on the "click to go to PayPal" picture, made payment and clicked the "back to Scrap Yard" link, and got the invoice screen (plus automated emails from Scrap Yard and PayPal). So far, once I get to the payment screen, I've always been golden.
I was logged in to the Scrap Yard store about an hour before the knives went up (it made me change my password again, so I was happy that I didn't get hit with that while under pressure to complete the order). Being logged in lets me select my profile name to auto-complete all the identifying info, so all that worked for me too.