No I got it . On big bikes, lower-gears can generate more torque that can run you wide. Shifting up a gear gives you less torque at contact patch and more traction for cornering and turning (friction-circle). From video you sent, note that his lean-angle is fairly constant once he's entered T14. He's already at maximum lean and actually decreases it slightly as he adds throttle heading towards T15.
There's traction-control happening here, so don't assume that "full throttle" application is what's giving speed through there. It's getting maximum-lean early on, so that you can get on full-throttle as early as possible before 15 for maximum drive down straight. The slowest part of sequence (real apex) is imaginary point in middle of track right after 14. Then it's full-throttle, decreasing lean and increasing radius after that as throttle is added. If you get full-throttle in 14, that's worth at least 10-15mph more on straight compared to full-throttle after "apex" of 15.
On Ninjette, there's really not enough power to upset suspension with weight-transfers. I'm pretty much full-throttle going into 14 after letting up brakes. Yeah, there's upshift to 4th after redlining 3rd-gear in between 14 & 15.
