Did their naps lengthen over time?
Charlie was a 3+ hour napper from the beginning of the transition to one nap. Olive takes a 2 hour nap, but a 3 hour nap would make such a difference in my life because she wakes up now just as Charlie is going down for quiet time, so they're not on the same schedule.
Did your LOs 1 nap lengthen over time?