not sure I understand the question(s), but I am surmising that the chassis batteries hit their eq charge of 15.5 first (rather quickly actually) because there are just two of them and they are fairly new - less than a year old. At that point I shut them off (started worrying about them), and let the house bank “equalize”. That took several more hours. Once everything was at rest both sets showed 100%, so life is good.
so….charging/equalizing is/was a time thing, and capacity is good (100%) so not an issue? I’m a little slow sometimes, so if I still don’t get it, just let me know.