I hvae been putting my 7 month old son to bed at around 6pm for about 3-4 months now, so maybe just put him to bed earlier. Its weird but it works, the earlier they go to bed the longer they stay asleep. My son has pretty much the same schedule as your little guy, except he goes to bed at 6pm, wakes around 3:00am for a bottle, goes back to bed, wakes again at 6:30am,naps at 9am (2 hours),again at 1pm (2hours) then bed at 6pm.At their age they should get a total of 15 hours of sleep a day. At five months they are just beginning to form a routine, so he'll adjust, but it sounds like your doing great. Also, I read "Health Sleep Habits, Happy Child" by Dr. Weissbluth and it really helped me understand sleep paterns in babies. My son's pediatrician recommended it and it has helped a lot. Good Luck!