Practice spinning sprints. Small ring on flat ground, try to get up to 160rpm or more. That will smooth you out. Even more: do it on rollers.

Regarding pacing in a sprint: it doesn't actually help. Every pedal stroke should be maximal for any solo race-winning effort shorter than 1:15 to 1:30. My bet is that your average went up because your improved form lead to a more efficient stroke at higher RPM. The loss of peak is probably just being tentative when your cadence is slow enough to feel the pieces of it -- but that's when it's slow enough that you probably wouldn't have hopped your wheel anyway!

Nice work on the improvement though. Once you get it in your muscle memory, you can be all-out 100% and fatigued and still keep everything on the ground. It won't take much more work for you.