I'm sure this has already been thought about.....
.... but surely as the inverter is software driven, you could get it to dynamically adjust the Grid Charge current (A) in order to achieve a desired %SOC in the desired time slot (of the 6). As an example, I want to charge overnight in the cheap tariff window from midnight to 7am. I set this as a charge time slot in the "System Mode" page with a deserted SOC of let's say 95%
Come midnight, lets say my battery is at 40% SOC, the inverter therefor can determine the capacity needed to reach 95% (55% of the total battery capacity) and it knows the window within which. to achieve it (7 hours). The grid voltage is (roughly) constant at 240 (although it also knows the precise grid voltage) so could it not work out what amperage to set the Grid Charge Rate to in order to charge it slowly such that it achieves the desired SOC% by then end of the time period.
Would this not be better in terms of battery health and longevity ?
FYI I'm no electrician or electrical engineer but have a rudimentary grasp of the V x A = W formula ;-)