The PO loses exactly the same amount of money on a reused stamp as it does on a counterfeit stamp.
Interesting statistic, do you have reference source for that statement?
Now if you are implying that free carriage, thus financial loss, of mail is the same if reused or counterfeit stamps are used; specifically neither produces any revenue, then you are not addressing the volume of reused stamped mail verses the volume of counterfeit stamped mail. Volume is needed to understand the cumulative losses of each.
It really sounds like you are trying to minimize the losses due to counterfeiting with your reuse comment. Also as most of these counterfeits are likely to pass uncancelled, they have a higher likelihood of reuse as well.