Russ sorry, I still don't really understand what you're trying to achieve. I think it used to offer a control to set the battery reserve level on the timed-discharge page. That control is now available in the 'battery' section (as operating range). But there isn't usually any reason to set that above the minimum of 4%. Except perhaps to keep some battery in case of a power cut?
Perhaps you wish to hold the battery's charge until 4pm, to ensure it's available in the the peak time. Timed-discharge can be to used to achieve that.
Or perhaps you want to ensure there's at least a minimum amount of charge at 4pm, to ensure you can get through the leak rate on battery alone ?