I'm not saying people don't use them. But %'s no. I tested with putting Left at 0 and right at 100 (For Right handed shooter) and yes it worked as intended. I'd have to see Dirk & Z-Bo using these moves going to the opposite shoulder. Have any video proof? I'm not talking face up's...
Here is Dirk Fadeaway's going to Right Shoulder...
https://www.youtube.com/watch?v=tXauvL75rdY
Z-Bo Going to his left...
https://www.youtube.com/watch?v=eyUbTltTTrM
And I'm talking post MOVES tendencies...