Update: I let the car do its job last night and woke up this morning to it 100% charged. Thanks again for all the helpful information -- I wish BMW was more thorough in its documentation.
I've set up Low Cost Charging for my i3 to run between 10pm to 2pm the next day when my electricity rates are most favourable. I've also set up a daily departure time of 7:30 a.m., only because it's required for the Low Cost Charging feature; there is no preconditioning selected. The problem...