I can't find the Ross Tech writeup on request vs. actual (can you provide a link?). I ran VAG-Scope and actual matched request, with a 0.3 second lag going up and going down, on full throttle. Max request was 2110 mbar, max actual was 2110 0.3 sec later, followed by an overshoot to 2180 0.3 sec later.

It did appear that boost fell slower than I would have expected, taking about 0.9 sec to fall to 1010.