Measure Download and Upload speeds

Nice tool which is also a lot quicker than speakeasy
However, I'm not exactly sure about its accuracy as down here in Brazil, I'm getting a consistent 520 kbps download speed but the upload varies between 108-657 kbps meaning that I can upload faster than download at times.
I've just uploaded two pictures of 1.7 MB in size and the rate on both occassions corresponded to about 100 kbps.
Actually, to me it looks like the higher (apparent) upload speed I'm getting from this tool seems more like the SUM of the upload and download rates.