Set monthly data limit for internet proxy (squid) users

I've been struggling to add this functionality as well. The problem with squish is, it's squishing users that is not supposed to be squished.

The workaround that I used was to use the daily data from lightsquid stored in /var/lib/lightsquid/report/<date>/.total. Since lightsquid data is updated every 10 minutes, it also gave my squid setup the ability of an almost "real-time" quota capability.