I'm not familiar with this particular medication - so I don't know if it's short-acting (like Ritalin and Concerta.. take it now, effect starts now, out of your system in well under 24 hours), or long-acting like some of the a/p medications.
If it's short-acting, and you are starting it later and seeing him crash at supper... I'd be guessing he'll be in trouble next week with school, because taking it earlier will mean "crashing" earlier...
If it's long-acting (has to build up in your system and the dosage then just maintains that level), then I'd suggest figuring how how long between "dosing" and "crash", and time the dosing to coordinate with bed-time or a little past bedtime...
