Tax Code with Amount Range Type Rate behaviour

Hi, just a question, this is not found in the user guide or the window help. When setting up a Tax Code in Tax Codes form with a Rate of Type Amount Range, the amounts are those accumulated for the period in which the new tax needs to be calculated.

Now, in order to sum the accumulated amounts of previous invoices in the period, is the invoice date or the GL date taken into consideration? Does anybody know how it behaves?

thanks