Fact is, if they (somebody) would take all your hydrometers away, there would be nothing abnormal about your battery.
I could post here 1/2 a day about weird stuff my batts were doing in the 2 1/2 months I was on solar only. But they were still performing to my needs, even tho the voltages were weird at best. And I sure dint need no hydrometer to prove that they were indeed acting normally for batteries that were off grid for that long. Now that they have spent a week on the PD converter charger, all voltages are back to normal again. You can't fix what ain't broke !