PST is not the same as GST in that it is not offset with what you collect. The amount you collect is simply submitted to the Minister of Finance in your Province. You are entitled to a "Commission" on each remittance.

When contractors pay PST, the PST amount is incorporated in the cost. For instance: You order fixtures online for a bathroom reno. The bill is for the Fixture ($100.00), Delivery ($10.00)  and Both Provincial and Federal Sales Tax (in BC &% PST + 5% GST). The bill would be recorded as $110 (Line Item) + $13.20 Sales Tax.

The Client Invoice would be $123.20 (cost of the fixture) Line Item = the appropriate Tax Code.