Upgrade from 11i - testing out AR Sales TAx in R12/eBtax

Hello

We are testing our upgrade to R12.1.2 from 11i.   In AR and OM,  it seems we can get sales tax to calculate by using either the Tax Classification Code choice of "Sales Tax", (which makes sense to us)

But its also working fine if we select a Tax Classification Code from the list of choices called STANDARD.   We are not familiar with this code because it did not exist in 11i.

Does anyone know which is correct?   All our customers came through the upgrade with a default value for "Sales Tax", so we are inclined to use that value.   Just wondered if anyone else had observed this "STANDARD" tax classification code also corerectly computing a location based sales tax.