Why not just have the timer go off every second or two? I wrote a nice DCC Speed Window script that displays total upload and total download bandwidth (and a combined up+down total) in a nice mini window at the top right of my mIRC window and it updates every couple of seconds. Everytime it updates the display, it also checks the current bandwidth for both upload and download against the records and changes the records if necessary. You can then echo the records to yourself or display them in a channel. This is always running on my computer and it doesn't slow me down at all with it checking that often.
If you are interested in it, let me know and I can display it here after I am at home.
