Your "test" version is too open ended... and allows for all kinds of errors and (estimates!?)
Estimates are no good in a test.
Many people here have large odometer errors.
So their data would be unusable.
Only if their odometer error was accurately measured and then compensated for would their data be any good.
That is why for a real head to head no bullshit no estimate test... you fill'em both up and ride the same path.
And to use the average fuel consumption over a set period or mileage is no good either.
It would tell us only what that particular persons fuel consumption is... but does not compare the fuel consumption of the 2 choices head to head, doing the same amount of work for the rider.
If I want to fly down the freeway at 100mph or pull a dragrace start... (neither of which the moped can do)... then you have an unequal test.
And the lesser fuel mileage I get is worth something tangible when I cut my trip time (compared to a ped) from 1 hour to a half hour because my average speed was twice as fast.
If you are claiming economy... then we run for economy... since I can ride for economy anytime I want to... but don't usually.
And NO DANG PEDALING ALLOWED !!!!!!
(coasting is OK though)