People are free to enter any data they wish into the database. For my HCH the "by hand" results are always about 3.5% lower then the display shows. Personally I think the lower "by hand" numbers are more honest so I use the "by hand" method.

The Database has a check box for the method you claim to use. If you look at mine you will see:

Calculation Method: By Hand

The site owner Jason uses the other method so if you check his car out (down on the right side) you will see:

Calculation Method: By Display