BC PST becomes part of Purchase amount?

It just came to my attention of how our AP team has been handling invoices from BC now that they have switched back to the PST/GST model.  

If a purchase is $100 + $7PST + $5GST, they will enter the purchase amount of $107, then delete the PST that is calculated by GP and manually correct the GST amount to $5.

The reasoning is that they do not want/need for the PST to go to a tax account on the B/S.

We are based in Ontario and don't need to track the PST paid in BC

Our controller seems to be okay with the practice but something doesn't sit right with me.  It seems that we are inflating our purchase amounts - but I do not know where else to stick the PST.  Any comments on how you are handling the situation?

Thanks