I know that some recommend limiting the 1st nap, rather than the 2nd... but it looks fine to me. I think it makes total sense to keep a good morning nap and, as it moves later, eventually eliminate the pm nap.
Just don't be surprised if 1) some days you fight for the 2nd nap and don't get it (so earlier bedtime) and 2) DS is a little cranky when woken after 30 min (because it's not a full sleep cycle). My understanding is that it takes a few days for them to get used to the shorter nap.
Good luck!