We have something similar now, except for the difficulties at BT: bed at 9 pm, asleep in 5-10 min, but then up at 7-7.30 am. We used to have wake up at 8-8.30, so we are at 10-10.5 hours night... And tonight we had a NW at 10.40 pm, he wanted to be taken up, as if it is already morning... I don't know if it is still the 18 months phase (DS is almost 19 months), but I've read somewhere that it could take also a couple of months to adjust.