i see this thread is old
but for future reference:

raymonds have a setting that determines the BSOC (battery state of charge)
it does this to determine if the same battery has been reconnected

if you take a battery off thats low on charge
and the next battery is less than 75% greater in charge then the BDI will not reset to the new battery's level
it will continue to read the old percentage (even though you did put a stronger battery on it)
75% is the default setting it can be lowered to 55%

so seeing you got 1 battery to 4% id imagine the others you have arent in the greatest of shape
this might explain why it didnt reset even with another battery

i had a cat do this a few weeks ago (some cats use the same software)
i had to lower the BSOD % in the menu to reset the BDI (ramond calls it the OD- operators display) with an older weaker battery

to access the menu and the analog potentiometer test
you have to know the superword

you say you have the book
if you look up test A03 it has how to test with a voltmeter
its easier if you know the superword though
most likely your pot is bad or out of adjustment
use the midpoint reading and look for smooth sweeps on you DVM as you move it foward and backwards
(key on dont step on the pedal, backprobe the connectors that they ID in the test)