Thank you Steve!
Don, it sounds like I could have save a ton of work doing it your way. I've spent 10-20 hours so far puttying and sanding all the spots that tore out from the bottom of my porch bracket cuts, and damage from tabs. Just to clarify, you are plunging the compression bit in 3/4 deep into the plywood and rough cutting in one pass? Wow. Though I was cutting pretty fast at the end -- I got it down from 45 min per bracket to 15, and was cutting cleanly at 324 IPM, or 360 IPM but with 2 flaws, always in the same mirror-image locations. It was uncanny. I don't understand why. Actually, I took pictures, maybe someone here can tell me why...
It made a ga-BANG noise when it did that, but the rest of the 2'x4' sheet was cut cleanly. I thought a chip just got caught and it was a fluke. Then it happened again in the exact same spots, so I went back to 324 IPM.