I don't know if I will be much help or not but I will try.  My husband has CHF -viralizing non salt wasting.  He has been on the same dose of medication since he was 5 years old.  He is now 40.  He takes 35 mg of Cortef daily.  I believe they attempted a change to that years ago, before my time, and were unsuccessful.  He has been stable on this dose for years.  We live in a small community were there is not much knowledge of CHF so we are depending on the good lord to watch out over him!!  Hope this helped.