If the tariffs have been implemented to prevent staff from surrounding office and construction site from using the facility free of charge and clogging it up during the week thus not allowing genuine shoppers the opportunity of parking then surely a preferable strategy would be, yes, to implement a pay for park Sunday thru Thursday and then just have the barriers open on Friday and Saturday ie free parking when offices are generally closed but genuine shoppers are out in force. Right now, it is the genuine shoppers who are being penalised and not necessarily the office workers who have been "abusing" CC parking facility. As I said earlier, I believe the fee is reasonable  but maybe its a point of principle - who knows!!