I have two SWCAH boys,  8 and 10 years old.  My youngest struggled when he was younger with height and weight issues-  he was 8lbs at birth and 20 inches,  which put him on the big side, and he just slid off the chart for height and weight-  I think his weight at one point was 0%  and height was at about 10%-  his levels were usually very good, although he did need a lot of florinef (4 tablets per day).  Anyway he is 8 years old now and he is at about 25% for height and 50% for weight,  he is a great little athlete and is a ton of fun to be around.  I am not sure why he dropped off for that time period- really from 6 months on.  He has recently really caught up-  good bone age always????

I know it is hard not to worry -- I worried and he was my second CAHer.  If your sons levels are good try not to worry-  kids really do come in all shapes and sizes.

Good luck to you.