I would not increase a child’s dose without the advice of their ped endo first.  My son has LOCAH and our endo from NIH suggested we wean him off Cortef because his bone age is of an 8 year old and he is 10yrs old, so he has plenty of time to grow.  Also, they said if puberty comes after 10yrs old for a boy, that is within the normal range.  If your sons have classic and are salt waster, then that is a different story, but be careful not to over medicate because additional problems may result.