Originally Posted by Kolenka
Using a password manager to fill out forms like this can help.
Actually, I think that's what caused the problem. I used Roboform to fill out the billing address but I may have used Roboform a second time to enter the shipping address and it overwrote the billing address.
That happens because some genius programmers can't use the obvious names for fields (shipping_address, shipping_city, shipping_state, billing_address, billing_city, billing_state) and therefore it confuses the auto-entry.
Most sites have shipping and billing info on different pages but some get it all on one page, like Weaknees.