My son was always on a twice a day routine with the dose split evenly between am and pm. However, in his case the 2-3 hours before the pm dose was always difficult and it was decided to give 3/4 of his dose in the am and 1/4 in the pm. He has thrived on this regime and we have had no problems with weight or illness. He is now 8.5 and has not had his dosage changed for 3.5 years since his weight to height ratio has remained constant. Since each child has a different metabolic rate we kept a record of his day and included things like energy levels, mood changes etc. After a while a pattern emerged and we were able to show our endo this and the dosage regime was tinkered to suit him. I hope this helps