If you have an '06, DO NOT tell him you want auto up-shift. I don't think he will do it for that reason. The flash is to solve a sloppy 1-2 shift.
Nope. The Predator can make it NOT upshift if it upshifts to begin with. Think of it as 2 options. Stock or NO upshift. If Stock == no upshift then the Predator won't do anything for you.