2016 Jazz Blue A8 Scat
I'm not sure what' you're seeing, but the cylinder filling is already dropping before the switch. Switching later is just going to make it drop further before the changeover.Looks like you may need to bump the rpm range up for the runners to switch. A couple of hundred could be enough to kill that drop in power. I have seen that tuned out by doing that.
Also, notice the shift points. You really don't want the runners flopping back and forth at each gear change. If I had a larger camshaft that would carry VE higher and a higher rpm limit accompanied by higher shift points, moving the switch point up could make sense. Or just switch to an Edelbrock intake.