Kirby is a bouncy boy!
Bounces happen when 1. they drop too low, 2. they drop too fast, 3. they drop into numbers their body isn't used to anymore (or any combination of all 3)
Although 174 isn't "too low", his body has probably gotten used to being much higher, so even though there's no danger of a hypo, his liver still reacts like there was and releases stored sugars and hormones to bring him back up. He also dropped almost 300 points in 4 hours last night so in Kirby's case, both reason 2 and 3 are in play. It can take up to 6 cycles for those hormones to clear out again.
Bouncing is a normal (but frustrating) part of treatment, especially at first. Usually, as they spend more and more time in normal numbers, the liver re-learns that it's OK to be there and stops over-reacting so much so the bounces won't be as high and won't last as long.
You might try to start getting a +2 or +3 on every cycle (if you can). A lot of times those tests can almost predict what's going to happen later in the cycle. If the +2 is lower than the Pre-Shot, that's a strong indicator that you need to plan on getting more tests in later in the cycle because he might be going much lower. Also, if he's dropping quickly, you can intervene with some food to try to slow down how fast he drops.
Hang in there!!