Amnesteem 40 mg vs. 80 mg. Just realized after 14 weeks my son has been taking wrong dosage

My 17 year old son (weight 175) was prescribed Amnesteem, December 22, 2015, I just REALIZED he should be taking two pills daily (40mg x 2), instead of the 40mg. I will call our doctor tomorrow but realized this after the office had closed for the day. After reading some reviews, is it correct that he should remain on the 40 mg daily for 30 weeks instead of increasing to 80 mg (14 weeks complete)? he was supposed to take 80 mg daily for 20 weeks.