Yes can use 4 cost buy 4 use 2 u end up paying 4 2 so that is where the 3 rd bogo is for.
Yes I have done the transactions, only one location would not use my 3 rd bogo. But the cash register will beep if u cannot use 3 but the cashier has to ring it up first.
Last question. If they total has not been pushed the full price is what shows up. 50% is calculated after the total button is pushed.