As has been stated previously, you really need to try to marry up the PC and HC. Is she changing things from the lessons with the PC, even small things that you may not notice but a HC that happens to be a PC might? Are things changing when she is facing live batters which is very common with the jump? Could be a whole host of things. Only other thing I might suggest is to ask your DD's PC if they could possibly attend and observe your DD during a practice. Doing this will provide an opportunity to marry up the PC and HC.
I am a hitting coach and I have never had an issue talking with a HC if they have concerns about what I am teaching or what a player that comes to me is or isn't doing. Some times it is a difference in philosophy, other times it is the player changing something she has been taught - either way it is a lot easier to get things sorted out early because neither like to hear from the kid "coach so and so says that is wrong".
I am a hitting coach and I have never had an issue talking with a HC if they have concerns about what I am teaching or what a player that comes to me is or isn't doing. Some times it is a difference in philosophy, other times it is the player changing something she has been taught - either way it is a lot easier to get things sorted out early because neither like to hear from the kid "coach so and so says that is wrong".