I really like this site. But I have avoided using the partial full up option for 3 reasons: 1. I want immediate data; 2. I'm not sure I trust the algorithm not to skew the data, because I've seen some really wrong entries when comparing with other Accords of the same year, and just other cars in general, which I can only attribute to bad data entry or bad calculation. I rarely partially fill, and when I do, I fill to an exact gallon mark rather than a dollar amount; 3. I trust myself to save the correct data and enter properly, since I'm more concerned with tracking MPG than costs, and I was tracking it long before I found this website. My one experience with using partial fill I didn't like and deleted. I just add the gallons from my partial to my complete fill checking total mile run since last total fill. Works better for me.