Doing it right?

[iNJD]

Hi all,

New to the site and just wanted to ensure that I am entering the data for each fuel up correctly.

On the "add a fuel up" page it asks for the "km since last fuel up" of course entering the figure displayed on the trip-o-meter just before filling up and resetting, however as for the rest of the questions such as "liters, total cost" etc am I correct in inputting the data for the fuel up I've just done?

Also..

Have just inputted my first fuel up and have a average MPG of 105.8 when the miles covered was 90.72 how is the average MPG higher than the miles covered.

I have trouble understanding how MPG works at the best time of times and aimed to use the site to do the math for me, now I'm even more confused.