How to keep historical data when source changes

[FernTurpin]

How is that for a title? LOL

Hi All, so I have a Pivot Table that queries a database and returns the following info
Date invoice was "posted", invoice #, amount, and technician.

Now, this report is printed every 2 weeks.

This report allows me to pay our service technicians on the vehicles they repaired during the previous 2 weeks, based on when the invoice was posted.

It IS possible, that an invoice can be "Un-Posted" and then "Posted" again in the event of an error on the invoice. In this case, if the unposting takes place after the report was run, then the same work order can appear on the report the following week.
My question is how can I keep a master record of what appeared on this week's report so that if an invoice is un-posted and re-posted, then it wont appear a second time?