at 7mo some babies are down to 2 naps a day, some still on 3, it all depends on the individual, We were still on 3.
Most babies still on 3 naps will have 2 x 1.5hr naps and a 45min catnap in the afternoon. If yours are having 1 x 2hr and 2 x 1hr then they are absolutely getting the right amount of sleep, just in a slightly different way!
If the routine works for you then I would leave it as is, they will extend their awake times themselves when they are ready to drop the catnap.
The only thing I can think of is they might be undertired and ready for some more A time, so to try to extend their awake time after the first nap, if they wake at 10.30, try to keep them up a little longer before their next nap, this might help them sleep more. Too long and they wil get overtired and sleep less so I would try just maybe 10-15mins to begin with.
hope this helps
K