the second logs too big to fit into a good graph just too long.
split up another couple of sections where vnt drops near 20%
heres first section looks to be going up through gears
and heres a section from middle
the other stuff is there for reference but little reason to stick it into graphs.
your plan to catch it on a day where it feels this braking effect is the way to go now as you have plenty of data to compare to.
don't forget a quick log of revs, boost pressure , and boost temperature, and maf temperature.
will give a good idea of efficiency at full boost , when vnt is near 20% to see if boost temperature spikes up or not.
decided to add the boost/maf ratio ontop of the full log
im not sure what you've done but the last few logs with maf on were seeing this ratio down to 1.5 and upto nearly 3 which is what was suggesting boost leak, or leak after maf.
this last log looks muck better closer to steady 1.9-2.1 except when high boost , low vnt in first section which I might suggest is nearing the limit of the maf sensor reliable range especially at the high revs, so really this might be a sort of false reading but its still what the ecu will use.
heres the old log im referring to ratio boost/maf looks much worse
you can see its all over the place compared to the your log.
id say if all you did was inlet flap, put back to standard and repeat , if you did any fittings or hose clamps you may have fixed a leak somewhere.