well, Obviously you are taking the club too far in than what is usually **recommended**. My approach to golf is a lot simpler than other people. If you are used to taking the club too far back on the inside on your backswing, start your downswing more toward right field. The problem here is that too far inside and you are starting the downswing along the target line and that will usually cause a over the top move.
Never had a golf lesson and never care to have one.Don't read any of the golf pub anymore but isn't it just common sense that if my body is coming inside on the backswing, in order to square it, I have to start it outside on the downswing. If My backswing is more upright, I start my downswing on a more downward path,If I am going straighter back, I follow staighter through,etc...............................
I don't know about other people,but just focusing on reciprocracy, I could hit the ball pretty straight with as many different plane as I want... and I could even work the ball -cut it, draw it, hit it high and low depending on the plane of that reciprocracy.
Geez, all that, and really my point is that another option is that you try to bump your hip toward right field to start your downswing.That shallow out your club and start it more inside-out. It might not be the ideal way,but it could be a quick and dirty fix.