Notch more than 25% deep on a load bearing wall stud. Help!
user71123,
With the 2x6's notched uneven, you won't get optimal support for your tv. The     1 3/8" notch is fine, but I wouldn't go deeper. You'll want to sister in (along side) your existing studs with 30" 2x6 blocks placed above and below the notched studs. In other words your sister blocks should be placed so the notched part of your existing studs hit center of sister blocks. Then you can cut new notches for your tv mount.  

I know it may be a lot of work since the drywall is already hung. The only other advice I can give is to return your tv mount, and buy one that's suitable for hanging tv's without notching, unless your local codes won't permit that type of tv mount. If permitted, so you can use a mount without notching, then you'll have to adjust placement on other studs or even a different wall. Good luck