When Riley first transitioned, sometimes he would wake at that hour mark as well, but a little pat would get him back down for another hour or so. If he is getting 13 hours total, it mat be enough sleep, just not at the right times. I know a lot of children just do around 11 at night, but I wouldn't suggest you mess with his bedtimes. It does take some lo's a while to adjust to the one nap.