They should also require the ISP to use a reasonable method to count the amount of data if there is a data cap. No matter how I count the data in and out of my gateway running OpenWRT, Comcast/Xfinity consistently counts and charges me for at least 20% more data with no discernible reason why.

I think somewhere in fine print they claim they get to round up to the nearest KB or MB every minute or some asinine made-up scale that only benefits them.