Provide calculation of GST and publishing of GST only when both GST and PST are present on an invoice.

The extracting and calculating seem to be already in place and correct. It's a matter of publishing.
The proposed function is when a 2nd tax is NOT active (PST) and the user uses the GST/PST BC extraction method, that it will only publish the GST amount (5%) and the PST amount (7%) will be added to the expense, NOT the GST (tax) amount.
This will calculate the taxes properly when both taxes are present.
This will allow the user to create a rule to extract both taxes, but just publish the active tax (GST).