they are outsourcing from an essentially imperial world to an essentially metric one.
Or the other way round!
You are right though about the need to take a holistic look. Most industrial batteries are constantly under load and therefore to keep them in service they are constantly experiencing charging/discharging cycles.
The Li-ion units on the 787 are
standby batteries in the true sense of the word ie. they stand doing nothing for pretty much all of their service life only occasionally being called into use.
If I was the engineer overseeing this process I would be looking at this and at things such as 'were the batteries that had to be replaced ever used in service'. Used as in had a real load applied such as starting an APU when this couldn't be done from from the on-board gennies or GPU, or did they just sit there in the bays in a constant state of 'charge' with the occasional test.
A key part of this is the data which shows how many replacement batteries were from the aft (APU) location or the fwd (main) location. It is the answers to questions such as these that may reveal the problem as much as looking at individual voltage/temp/float charge data.
Good luck to them :-)