In a perfect world we'd have both the total paid and the price/gallon. I personally like to see price/gallon so I know roughly what gas has been going for at the pump. (The total doesn't tell me that.) Unfortunately, space is limited there, and I don't think we can have both. But maybe we should add it to the "View all fuel-ups" page. Then you could see your totals with each fuel-up.
I'm noticing a bit of a variance in the dollar amount. I admit its only by a few cents either way, just an anomaly I noticed. By habit I always try to fill up to the nearest dollar. RARELY ever under the nearest dollar, USUALLY AT the dollar, sometimes a few pennies above. I've noticed that I'm sometimes out by as much as a few cents in either direction. Suppose its going to even out after time though.
I took a look at your fuel-ups, and I'm guessing the pennies difference you're seeing is related to rounding. We store everything in the US units. So even though your car is set to km and L, we convert those amounts into miles and gallons when you fuel-up. And we convert the price/litre into price/gallon.
I went through and re-calculated the totals just to see if the computed and stored total at fuel-up was different from a newly calculated total—and everything checked out ok. So next time you fuel-up, you might check the total it reports back to you and see if it's accurate. If there's something wrong with our method for computing totals we'd definitely like to get that fixed.