Can I change how GnuCash calculates sales tax?

[Mike or Penny Novack]

This isn't a simple "rounding bug" problem.

Each and every jurisdiction charging a "sales tax" (call it that, VAT, 
or what you will) gets to set its own rules as to how that is to be 
calculated. Do you add up the items and then compute the tax or is tax 
charged on each separately and then the tax added up? Do you round off 
by normal rules for rounding or do you always round up? There might be 
additional variants, but given just these two possibilities means FOUR 
different ways to calculate the tax.

Needed would be a "table" of jurisdictions with the rule to use 
determining which of these four to use. Or more if supporting more rule 
variants (but I know we'd need at least these four).

Michael