Your validation routines think some of my fillups are unreasonably small (<1G) or unreasonably large (multiple tanks recorded as a single entry on a long trip), and will not let me add them. There should be a way to say "no, really, I mean what I typed, I don't need/want you to save me from myself."
To be clear, we're doing this because we've noticed a lot of botched data entry going on in the past week or so. People are often getting km and miles mixed up and reporting 150mpg type fill-ups that are skewing the data.
So we've come up with some simple boundary limits to capture some of the common errors. We'll likely be adding more, so if you report a MPG average that is 2x higher than anything you've ever posted, we can say "hey, that last fill up looks fishy, did you check x, y, and z?"
But I agree, if there is a valid reason for posting something beyond normal boundaries, we should make that possible to bypass.
Are you finding that the assumptions are incorrect on the error checking? Did you really put less than a gallon of fuel into your car or is it more the type of thing where you wanted to add data from three fill ups as one?
There have been several times where I have topped off one of my bikes with less than a gallon of fuel, to get on the same 'need to stop for gas' cycle as people I was riding with. The 'three fillups as one' thing I've worked around by splitting the data, NBD, but I've had to fake it and list a couple small top-offs at 1 gallon, which leaves my MPG artificially low.
Also, while entering this data, I've noticed that the site doesn't cope well with things like an odometer being reset to 0 (parts replacement), all of the tanks after that are giving really odd results. You can see what I'm talking about @ http://www.fuelly.com/driver/volta/stone-touring, where the calculated mileage is way off. On that page, the 'View All Fuel-Ups' link doesn't work, so you can't see the older data.
Looking at your fill-ups, it looks like you are tracking by tripometer in the notes field, so I'd say you should probably move tracking of MPG on that bike to trip miles reading instead of Odometer. Having the option for odometer resetting seems like a really rare case that I'm not sure will come up very often, so I'd say in the meantime, try tripometer data entry to get correct data.
The trip notes are actually calculated by the script I wrote to import my existing data, I added them in when things were not looking right. That said, I can accept that odo reset is an edge case, so I've massaged my old data to work around the issue and will use trip data entry for that bike ongoing.
This bike only has a single, mechanical trip meter. I do actually use it to track mileage since last fillup, since the bike is pretty reliably empty by 160miles. I simply had not been recording that number since I had the odo reading, so there are no trip values in my existing dataset. Easy enough to switch for new data, though.