at 6 months lo's do have a growth spurt...with that said your routine looks pretty good but i can offer some pointers..
if your lo wakes at 6:30 and doesn't have a nap til the earliest 10am his A time is too long. my lo is 8 months and doesn't have A time this long - especially in the am. that is probably why his morning nap isn't going past 45 min also. morning naps are said to be looked at as an extension of nighttime sleep - so the A time in the am is usually the shortest of the whole day, as the morning nap is usually also short (but i wouldn't think that short). i think if you put him down for his am nap at 1.75 to 2 hrs after waking in the morning you would have a better nap. if your lo wakes for the day at that time and u aren't trying to change the wake up time for any reason - i would give him his bottle when he first wakes up and then you will be able to keep him on 4 hr easy. i think the amount of A time in the afternoon looks ok and he is sleeping better so i would leave that alone for now.
i would make sure i was giving him a bottle every 4 hrs or so (not any longer unless it's longer due to him sleeping). it looks like you cluster feed in the evening but i am not sure that you need to do this now. i would try feeding at 7am, 11, 3pm, 7pm and see if the amounts he is eating improves, as it will help your day flow better i think. you may also want to try doing say a 7:30 bedtime and that may also help, as routines are usually looked at in a 12 hr period (ie 7am to 7pm)
i don't see that you do a catnap in the evening, and if your lo may need an extra half hour at some point (especially if you are putting him down for a nap earlier in the morning) to get him through to bedtime w/o him being overtired. with this the nightwakings may stop/slow down. once this is established let me know how things are going with the wakings, and if they are still happening, there are some other suggestions i can make that may help you. but first the days should be figured out - as one really does affect the other.
i know i gave a lot of suggestions - not to say to try everything all at once. before anything specific about night wakings should really be dealt with, i would get him on a more definitive easy routine (4hrs). hope i have helped some and if u have any other questions let me know!