These comments imply that you can make purchases with and without PST, therefore does this mean you need to use both 5% & 4.6729% GST on purchases.
For the purchase to include or not include PST how does the Supplier know if the items are going to be resold or not. E.g. Printer paper supplied to a stationery shop v’s an end user
To use the suggested above formulas to report the PST paid how do you propose calculating the total of PST purchases, you could group the PST affected expenses together on the P&L so it provides a sub-total.
What is the position with purchasing Fixed Assets, do they incur PST as they aren’t being resold
In the longer term @lubos statement “I guess the best approach would be to extend custom tax codes so you can enter both tax components GST+PST at 5% and 7% and mark PST tax component as non-recoverable.” would be beneficial as it could possibly also address the Withholding Tax issues that others are having - accept that one is an addition and the other is a subtraction