Mine always had long morning A time (up to 8hrs) and shorter afternoon A time (4hr). He only ever did 10.5 or 11 hr nights, reducing his nap didn't extend his nights, its just the way he was, needed a 2hr nap and a shorter night all the way up to dropping the nap for good (by which time nights were even shorter - after nap drop though 12hr day, 12 hr night).