I have a 15 mo. old son was CAH, saltwasting. For the first year his levels were great, always in the right range. Then all of the sudden his 17ohp jumped to 4200. I was VERY concerned. His endo told me that it wasn't unusual for there to be a big jump in an otherwise well regulated kid. She explained it in terms on not being able to perfectly mimic the bodies hormones levels, particularly when the kids go through growth spurts. She promptly upped his dose and we rechecked in 1 month. She said it was important to recheck quickly, but also to give his body a chance to adjust to the dose increase. His levels came back nicely and we checked again 6 weeks later. I haven't heard the results on the last tests yet, but if they are fine we will go back in 3 months. I think it is really hard to balance "being on top of it" with the fact that there probably will be some high reading periodically because this is not an exact science. I think I would see if the endo will check sooner than 3 months. If you wait three months and they are still high that would mean you son could go 9+ months with high levels. Good luck.