On the PO the tax code is defaulted, match PO to AP invoice, change tax code in AP not changed

Summary:

When the PO is created we show the PO amount including tax (GST). Then we match the PO to the supplier invoice and the tax information is copied across form the PO. But when we change the tax code on the invoice distribution line the tax code is not changed in the tax section of the invoice. It is not possible to change the tax code only the tax percentage. But we need to be able to change the tax code (and thus the tax percentage), as both tax codes appear in different columns on the tax reporting. The tax