If the test was to be falsified, why even bother with a test?
Because there were witnesses to him meeting up with this prostitute for sex (multiple times). If he did not try to put this to bed with a falsified DNA test, then a paternity suit could have been filed based on eye witness accounts, and then he would not have been able to control the test as easily. BC got ahead of the issue by planting false results in the media before any official DNA test would have been conducted.
Offer Roger $$ + cocaine for his dna-close enough.