Ritalin dosage 20 mg vs 10 mg | ADHD Information

My grandson was taking 10 mg Ritalin LA daily without success.  The doctor increased his dosage to 20 mg.  We started this transition by giving him two 10 mg daily in the morning and when the pills ran out, filled the new RX with the 20 mg dose.  The first day on the new pill we noticed facial tics, or more precisely, moving his jaw up and down repeatedly, especially when he was involved in quiet play activies.  When distracted or stimulated by conversation or TV, the tics went away.  Also, on the two 10 mg dose, we had very little problem with sleeplessness, and now we are battling to get him to bed before midnight.  He has early Kindergarten and needs his sleep.  Can the 20mg LA dose be a different formula than the 10 mg, thus making his taking 2 tens less of a problem than one 20?  Anyone have any suggestions? His abililty to function at school and at home have improved so drastically these new problems worry me.  It would be so sad for him to return to his adhd behaviors.