@georgeman:
I would have predicted the opposite, I thought that two simultaneous Speedtests were going to also exceed the limit, when combined.
What about two simultaneous downloads, from two different sites? Does that exceed the limit?
I found a proper alternative to this, the Captive Portal limiter. It seems to work in a different manner than the FW-rules applied one. I'm guessing it acts as a proxy to a particular MAC-address, and those even torrent won't bother with fiddling with.