P0A80 options

This is excellent data, along with your individual voltage numbers point at module 4 and 5 as being the problem. The rest of the pack seem to be fairly well balanced.

In my experience once the battery modules begin deviating in voltage a high voltage charger like the prolong will only temporarily mask the problem. Once battery module begin to deviate in voltage they need to be replaced, even full reconditioning doesn't fix the issue (have tons of data showing this). The underlying problem is lack of efficiency from those modules, after a rest period or several charge and discharge cycles they will deviate again.

The other concern is the location of the failure in the pack being block 2 and 3, the expected failure is in middle of the pack. Failures in block 1-4 usually occur due to sensing harness and battery computer corrosion. I would take a close look at those two components for any sings of oxidation. I recommend taking off the battery computer and looking at the circuit board side of the sensing plug.

 

Had you started using the Prolong system before the issue, you likely would have been
able to keep the pack in decent shape. Eventually, they will all fail, like any battery.

Time for the Sodium Upgrade!