The only suspicious thing is:
Katy tour 70M - single 500k
Gaga's tour 180M - single 250k
And in Katy's case yes this is more likely since song costs 1$ but In Gaga's case It's really weird how they can pay 100$-200$ to see the Queen live, but then can't pay 1$ for her song
While with the album It's obvious that PRISM rised because of the discount (in Fact the album has been discounted on Itunes almost half of the time It's been released)
ARTPOP was just discounted and It's already on track to enter top 10 on Itunes ...