I actually saw something similar in telco, where a carrier was rounding charges to the cent, but charging in fractions of a cent. So for example a CDR might be

I actually saw something similar in telco, where a carrier was rounding charges to the cent, but charging in fractions of a cent. So for example a CDR might be worth $0.001 but my customer was being charged $0.01. My customer complained, but in this case they prevailed because the contract said nothing about rounding. This can be really significant. They ended up having to compute the charges and send the carrier a bill for the difference. It was worth tens of thousands of dollars per month.