RedOne has had more hits without Gaga than she has without him.
RedOne's song for Austin Mahone is better than anything on ARTPOP except Gypsy [which he co-wrote].
If Justin Bieber sang this it would have been a bigger hit.
RedOne has three Hot 100 Top 10's that are not involved with Gaga - Fire Burning (#5), On the Floor (#3), and Starships (#5). Gaga has seven Billboard Hot 100 Top 10's that are not involved with RedOne - Paparazzi (#6), Telephone (#3), Born This Way (#1), The Edge of Glory (#3), Yoü and I (#6), Applause (#4), and Dope (#8). Correct me if I'm wrong, but I think your math is a bit off.