That's powerboost (which the biz support people say biz lines don't get
but they do, at least they did until they broke the new speed profiles in some areas).
Anyway, I digress...
The speed boosts are normal. I'm not sure why speed tests would be slower while VPN'd, but can you try downloading a large file, e.g.:
Are your sustained speeds after power boost the same with and without the VPN when downloading the above?--
"I drank what?" -Socrates