KT could be bouncing off of that 172 yesterday, this actually looks like the second blue bounce to this dose....Boo was a blue bouncer too for awhile (look at my ss beginning 8/12 - 9/12)!
It looks like historically, it takes him less and less time to clear them with the first one at this dose clearing after about 48 hours.
I know someone else will come along here....I don't think there's much doubt that you'll need to take a increase here shortly, but I would wait another day or so to let this bouncing level out, or to see if he bounces again.
He's finally reacting to the insulin by throwing you consistent, intermittent blues, and that you can and are effecting with insulin....it's getting his pancrease accustomed to the lower numbers that you can't effect(which is the bounce), so the waiting, lets that happen. It lets his body adjust to something lower and this is an important (albeit frustrating) part of the process! He has to accept this blue lower to be able to go even lower, and bouncing is a sign that he's trying to work it out.....Hopefully that makes sense! ;-)