Also interesting that apparently there probably was no F PUMP FWD or AFT CAUTION to prompt selecting the pumps off if the numbers are correct in the reconstruction and flight testing. What prompted the action to turn them OFF? There should have been a CAUTION after they were selected OFF though.
This is also backed up by the amount of fuel found in the aircraft.
Also it is apparent that if you fly a ball width to the right out of balance that you can reduce the differential in the SUPPLY tanks to "not much at all" ~ 32 seconds.
In "balance" the 135 flies left wing down - take a look at the STBY AI installation or the primary AI on level ground. So the differential if flown in balance might actually be greater than 4 kg.