Tax is getting calculated on Freight Line

Hi Experts,

I am having a couple of issues with entering tax lines on AP invoices.

1. When matched to a PO, sometimes tax does not appear in the LOV after entering a freight line and saving the record.

2. Also, when tax does appear, the tax gets allocated to both the line item and the freight line. We do not want the tax to be allocated to freight.

We are entering manual tax line and we have turned eBTax off (supposedly) by un-checking the  "Allow Tax Applicability" option for the Standard Invoice event class. (Are we missing something else?)

Please advise.