Roy,
You say you have 4 ea U2200.
Is that two pair just for the house bank?
If it is and you are on shore power and concerned, just disconnect the string that has the worrisome cell. Wait a few days and buy a cheap meter some where. Then see if the disconnected string has lost enough to be a problem, then check the battery with the bad cell and compare it to the other in that string.
If you come back here with that information, someone should be able to tell you how much problem you actually have.
Matt