I note your daughter only takes hydrocortisone twice daily - this seems to be fine for some children with CAH although studies have shown that it is generally insufficient in times of illness and during puberty (when absorbtion rates increase).  If she is taking these doses 12 hours apart, with hydro out of the system within 4-6 hours, it is no wonder her levels are high and increasing the amount of 2 doses will not alter that.   I am surprised smaller doses taken more often hasn’t been suggested or  another option is switching to prednisolone, which lasts in the body longer.