My son is also on Methylphenidate 20mg, he has been on the same dose for about 3 years. When we started 4th grade, this year, we couldn’t get through homework in the evening. So, now we take a smaller, 5mg, “boost” ever afternoon. It has changed our evenings dramatically for the better. But, as someone posted earlier make sure not to take it too late in the day or bedtime goes out the window! We adjusted the afternoon timing A few times before we found what worked for us.