18kpv AC Charge Mode window not using battery when full

The question is why doesn't the Inverter use the battery when set to Time+SOC/Volt but it will use it when set to SOC/Volt. Setting to Time+SOC/Volt prevents the battery from being used in the time window as if in Backup Mode (which is disabled) rather than Self Consumption. 

The reason is because any time there is a setting configured with timing, it will take over according to the time. Although the batteries don't need to be charged, it stays on grid and once the batteries hit that SOC configured to start charging it will charge.

I would expect the time window to take over for allowing an AC charge within that window.  I did not expect it to switch away from self consumption to do so and instead emulate Backup Mode. What is the difference then for "AC Charge Mode"  with time window with a SOC set and "Backup Mode" with a time window with SOC set.  They both end up turning off Self Consumption in Favor of using the grid.

Also, with "AC Charge Mode" set, if the battery is low it will prevent charging from PV within or after the window. Turning it off immediately starts charging from PV.

Reading the literature, it seems that by only using the grid during a PV Charge Priority window, and not allowing off grid mode to go from Grid Use back to battery use, it is the opposite of "managing surplus solar" or "optimize self consumption" or "minimize reliance on external energy sources".  So I can only assume there must be a bug.