correct. because the seller says shipped within UP only. the buyer should have a registration in UP as the goods are being bought and delivered there. Also, i suggest quickbooks to have a default tax location, or a default "inter state" or "local sales" global variable. this should help users who are selling goods locally generally and only if the place of supply in the invoice level is a different state, then it should select "inter state". this is a problem because sometimes during data entry, one can easily mistake 12% GST with 12% IGST. and the bill will come out wrong.
Let there be global default and the user should only have to select either tax at the time of sales or in the item master and be able to override the same per invoice.