I appreciate the kind words.
Fuel actually already has a feature exactly for this purpose;
restarting after a missed event, without losing previous data. It
exists in the App Menu (top left corner, where the name of the app is
displayed) while in the Fueling Event scene. You'll find it under the
"Data" sub-menu, titled "Missed (New Start)". Basically, its a
shortcut that sets a few key inputs in the Fueling Event scene to the
values that are used to identify a new [re-]starting point; Odometer
is set to Previous + .1, Filled Tank is set to "No", and Notes is set
to "Missed event, new start." if it is currently empty. The other
fields are left alone because one user may want to capture how much
fuel they pumped and money they spent for monthly/yearly totals, while
another may not care.
If you haven't already, you should take a peek at the App Menu for
each scene. Many of them provide additional features that are less
commonly used, but very useful when needed.
Also, the app enforces the vehicle's volume capacity because the
captured data is used to calculate various summaries, like the
estimated distance you could reasonably travel on a full tank.
-Rob