Originally Posted by mightyrick
IMHO, the coach is correct.
Don't get caught up in descriptions like this. Nobody can accurately reproduce any of this stuff on demand. The physics are too precise and fast. It has to come through the brain's learning through trial and error. In general, hitting a straight shot baseline-to-baseline requires primarily hitting the the back of the ball.
I'm not a coach, but I'd probably tell someone something very similar.
I am inclined to agree with you, except when the CC ball is coming in really fast. I feel like there is a critical speed at which you need to start compensating for the angle of reflection which is off the perpendicular axis from the racket surface. It might depend on a combination of CC angle and ball speed.
Does anyone consciously think about the different swing paths depending on either the CC ball speed or angle if you want to go DTL?