Q. "Why is it on the start procedure, at 12% N1 the throttle is opened past the idle detent all the way open then back to the idle detent,..."
A. Don't know, never heard of that procedure, never seen it done like that before...all the way open??? why????
I've (inadvertently) had the throttle ever so fractionally slightly past the idle position before when it's lit off and it went very hot very quickly...reckon if I'd followed the procedure suggested here (throttle opened all the way then back to idle detent) then my tail boom would probably have been a molten mass of metal pooled on the ground. Now I start it with the throttle slowly being opened at 12% and it lights off nicely before you even get to the idle stop position. Then steadily wind it on a bit more as you go past the 2nd ITT peak. No need to back off the throttle at all.