How does this traffic monitoring tool works?

[Woomera]

My ISP use traffic limitation of a certain GB per month for their user's.i found an strange bug in their limitation software,when i download or browse websites the statistics in their website for my user shows the amount of traffic i had and show the remain limitation.Till now everything is fine but the funny thing is that if i try to download a video/audio file with a direct link ex: http://website.com/download/video.wmv ,when i click on a link like this jetaudio automaticly get the link for playing and start to download the file.after the download is finished jetaudio plays the file and i also have a copy of the file,the funny thing is that after a download like this with jetaudio i check my statistics and it hasnt changed.meaning that it didnt count the download.

itried downloading another file with my download manager to see if it changes and it did.itried the wmv file again and still nothing changed.

i thought that they may only monitor HTTP ports and the wmv file is pointing to a link with a custom port but it wasnt.all my download using remote port 80 and still audio/video files are not getting counted by their software.

Now i wanna know why? whats the logic or explanation behind this? they both use remote tcp port 80 so whats the diffrence?

[CptMurphy]

The monitors basically work one way>monitor a port>log what is monitored. They may have temporarily taken the monitor offline, they may not be monitoring port 80, or maybe the software was reconfigured; or more unlikely, they are not limiting your total bandwith. There's a couple of reasons. The way I seen it, if you stand on the benefit side, keep quite and ride the bandwidth train until it lasts.