any idea what's going on?
Yes - at the time you did the test, your route through the VM network and out across other ISPs until you reach the speed test site - was able to get that speed.
Its like the M25 and other motorways, not all directions and all carriageways are congested at the same time. Sometimes you can do 70mph going one way, and only 25mph the other.
Try doing traceroutes to the servers as well.
pro - on THFB - sync about 17.2mbps - BQM