Bangs head against wall, I cant remember how many threads about speedtest.net being absolutley guff for these kind of readings. Especially through peak hours..... VM as far as I know are not putting the new (better) limits on till after New Year, although their website has updated, or if its being rolled out across the UK in stages during January, I have no idea.
I am also aware that some area's are also getting better throughput than others due to take up of Bandwith, luck of the drawthere I am afraid.
Was thinking the same thing. People take it as gospel. I feel sorry for ISPs sometimes.