[gone-ot]

...no, the SGII's FILLUP function is reporting how many gallons of gasoline it "calculated" as being used, you enter how much was "actually" used.

...it's part 2 of Step 4) Calibrating Your ScanGaugeII process:

Part 2 - Your Second (or subsequent) Fill Up:

1) When the tank is around 1/4 full, fill up your tank again. Be sure to let the pump shut off automatically.

2) Use the FILLUP function to tell ScanGaugeII you have filled the tank. From the Home screen, follow the sequence: MORE>FILLUP>

3) The next screen will show the amount of fuel your ScanGaugeII believes was used since the previous fill up. Use the upper left and right function buttons (A,C) to adjust the amount of fuel you actually put in the tank. <---this is where you're actually "calibrating" the SGII.

4) Push the DONE button.

5) After pressing DONE, the fuel COST screen will appear. Enter the cost per gallon/liter and press the SAVE button.