If you were camping at an RV park, plugged in 24/7, which is what all PD charge controllers are designed for, it would be a non issue.
Boost is not recommended if you are plugged into a power pedestal, the charge controllers assumption that all of us pay to hang out at RV parks. Some of us don't do that, so our parameters are a bit different when off the grid.
When you are dry camping or boondocking... all the parameters change. So should the instructions. Charge in Bulk mode, always, on the generator. Time = gas burned = money going out the exhaust at $4 a gallon, or thereabouts. Buying replacement batteries a little bit sooner and running boost charge is cheaper that turning gas into heat and not maximizing the boost feature when charging to make amps. Battery life lost is insignificant compared to fuel expenses running a generator at an inefficient charge rate. Bump that voltage up, charge in boost mode or bulk mode, the batteries will take it, easily.
Battery 2, for sure, is at the kind of numbers you want to see for SG. Wish you had a real glass hydrometer. Battery 2, tomorrow, if it's never been done, is ready for Equalization process at 16V, to really clean up the Specific Gravity across all the cells. Keep charging until you get a 16.0v reading. or until your Vabs stops climbing, and then turn off the device that can get you to 16.0V. Take a SG reading then, the battery acid should be thoroughly stirred after equalization, and ready for measurement.