I have the same issue, different pumps shows results that are way off. 10-15% off. Which difference is huge IMHO. Unfortunately pumps are set up with not the exact accuracy so you can put like 7 gallons of fuel and the pump will show you 7.2 I've read somewhere that here in Poland pumps accuracy have to be in +/- 10% range. There's no way to check the amount of fuel that you're pouring into the tank unless you'll use a canister and some other measuring device. That could be an interesting experience anyway
