Vertex Q Series and Tax Amount differences

We are using Vertex Q series with E1 9.1.  Our issue is that we are calculating taxes base on the Ship To address on the PO.  The supplier is calculating taxes on their location, a completely different Geocode and tax rate.  When the AP Clerk is creating the voucher match the gross amount does not equal the total amount on the invoice because of this tax rate difference.  Is there a workaround without having to change each individual line tax amount?  There could be many lines on this invoice.