LauraKHi Sam,
Several years ago, my daughter would come home from school every day with a bad headache. We switched to circadian rhythm dosing, and the headaches disappeared along with growth and weight problems my girls had been experiencing.
If you are happy with his control on your current dosing schedule, and he is a healthy weight and is experiencing good growth, he may just need a little booster dose at lunch. In our experience, the timing of the doses is very, very important in maintaining good control without side effects.
I can be reached at lgkovalcik[at]knology.net (replace the word in brackets with the @ symbol).
LauraK