J.P. Instruments EDM 930 Primary Pilots Guide - Manual (Page 36)

For Your Safe Flight Page 31
Example A: Aircraft has two fuel tanks with internal tabs.
You’ve preset: ‘MAIN = 66’ (33 + 33 usable)
‘AUX = 16’ (8 + 8 usable)
When you refuel:
‘MAIN 66.0 GAL’: use this shortcut when filling to the internal
tank tabs.
‘MAIN+AUX 82.0 GAL’: use this shortcut when filling to the caps.
(only one tank is shown in each of the two scenarios)
MAIN+AUX 82.0 GAL MAIN 66.0 GAL