Because she has fallen from her regular 10-15% in height I would be concerned.  This happened to my daughter.  She was at 25% and slowly fell completley off the charts.  This is when we decided to switch her schedule for meds.  She started life on 2 times and day, then 3per day.  Now she is on 5 times per day.  It’s really not that hard.  We were able to lower her total dose several times this way.  She is very sensitive to side effects of the meds and traditionally dosing was not working for her.  She has a fast metabolism and a large dose didn’t last as long as it was intended it just caused problems.  So we dose in smaller doses every 5 hours or so and she is growing beautifully!!  Her father and I are both tall and she has been at the 75% now for 2 years with bone age doing well.  She takes meds at 3am, 7am, noon, 5pm and 10 pm.  Good luck.  I know this can be frustrating.  We switched endos over this for the exact reasons you are stating.  We now have the most amazing endo possible.   She is so personable and we spend at least a 1/2 hour just talking with her about questions and concerns before she even examines our daughter.  WE love her!!  Good endos are out there!  Keep looking.  Julia