Mike, first you are the consumer and the owner of your own golf swing. If you have decided that Tathata is the program for you, then why would you confuse yourself by listening to other voices? On the other hand, if Tathata doesn’t speak to you in a way that helps bring out your greatness and your PGA instructor does, then go with what works.
What you could try is to continue with the program and as you see improvements in your strike and in your motion talk to your instructor about what you are learning. He may be interested especially if you are making progress and may want to check the program out for himself.
I value loyalty, but only to the point where to what or to whom I am loyal continues to be beneficial to me. Once that loyalty no longer brings the value then that loyalty is no longer serving your best interests.
Value the time you spent with your instructor and be grateful for what he has taught you to this point. And value what you are learning now and stay focused on the work you are doing now.