P0411SV Speed Voucher Entry Population of Tax Fields

When using P0411SV Speed Voucher Entry, the Tax Explanation and Tax Rate/Area fields in the header do not get updated when the supplier changes.  For example supplier 1 has the tax combination of V/AUF, however, when entering the second voucher which is to supplier 2 whose tax combination is V/AUIC the tax fields are populated with supplier one's tax combination.   This has the ongoing impact of the taxable amount and tax amount being incorrectly calculated based on the initial tax combination of supplier 1.  We are on 9.0.  Has anyone come across this issue?

Thanks