Does prevacid dosage need increased?

This is according to http://www.marci-kids.com “your child, who is 4.5 months old and weighs 8.6 kg, should receive a dose of 13 mg of Prevacid delivered 3 times per day for a total of 39 mg per day.

The recommended amount for each dose can be safely rounded up to the nearest available dosage form (7.5 mg) without risk of overdose or side effects (Example: A recommended dose of 6 mg given 3 times per day should be rounded up to 7.5 mg given 3 times per day, for a total of 22.5 mg per day).
Prevacid 15 mg Solutabs (lansoprazole) are scored and can be broken into two halves, each containing 7.5 mg of lansoprazole.”