Yes.
It is quite common for sellers to adjust the total to be paid by fiddling with the shipping charges. EBay does not allow post-purchase adjustment of the price part of the invoice.
If your seller is having a problem, tell her to bill you directly from Paypal and to put the eBay transaction number into the text box of the description.
When you pay, both of you will have to mark the item Paid manually, because with this billing method it won't happen automatically.
