Well for me it is working as I have it set up. I guess it is :oops:
I have mine set to 1000 kb/s in the settings and then when I close the Settings, the status bar on it it shows "No Limit". When I left click on the "No Limit" setting, I change it 20% and the speed decreases to 200 kb/s. I just did this and it hasn't changed back to no limit. As far as I can tell it is working as intended.
But don't know why you would want to go less that your internet speed. I guess if you need to do something while Alt.binz is running, maybe that's what it is for. But I always leave mine with No Limit.