Posted - November 17 2010 : 12:56:16
I ran into this on a customer site and thought I would post a note about it in case someone else encounters it.
Once I solved it I didn't go back to see if it affects all transactions or not, but it looks like it certainly could. Essentially what was happening was the customer had a shipping profile setup in their PayPal account from their previous web store that was based on order dollar amount.
What made it come to my attention was when I was implementing a free shipping promotion. Everything looked fine on the VPASP side, but more customers were abandoning their carts than normal.
After we contacted a few of them we got complaints about the shipping not being free as promised (in VPASP the orders showed free shipping as they were supposed to). Since most of their orders go through their merchant account (and the promotion was working fine there), it took a while to bird dog this down to a PayPal specific issue.
I ran a dummy trans on an item that wasn't in the db (the site uses calculated shipping by weight) and sure enough the VPASP invoice looked fine. It handed the transaction over to the PayPal gateway and a shipping charge popped up out of nowhere.
Now I was thinking about going through the PP gateway and rechecking all of the shipping subs. Luckily before I dug into all of that the customer happened to call me and I got their PayPal login. Sure enough, the mysterious shipping amounts lined up perfectly with the dollar amount shipping scale in their PayPal profile.
A quick deletion of the PayPal shipping config and everything works as it should.