You can talk to different coaches and get different answers to the same question. Early on, it is important to.follow one coach and follow what they say. As you get more advanced, you can mix different ideas, but as a new player you will just frustrate yourself. It is all about where you are at as a player.

I release much higher up, basically at waist height. I bowl one handed without my thumb so I'm somewhat limited in how I can move the ball during my swing.

@@MikeDCWeld you are an exception to the norm. Bowling without the thumb, and only with one hand, puts a severe handicap on the ability of your arm to move. I have the ability to change my release height if I need to loft the ball over the heads, but my normal release clips my pant leg right beside my ankle at release, just like most pros.