Worcester Parking Charge confusion

I've just been told a tale of parking at night in Worcester. It seems in a least one car-park (Copenhagen Street) the charges have been altered for a particular period. For 1 hour the charge is £1.20, but for the period 7pm-9pm the charge is only £1.00.

So if you arrive between 6pm and 7pm and wish to use the car-park until 9pm how much do you pay?

If you said £2.20 congratulations you are correct as confirmed by Worcester City Council itself. Sadly though you'll still get back to your vehicle to find a Parking Charge Notice because, it seems, no-one's told the attendants this.

"Why has a fine been issued?" I hear you ask. Because the ticket will show your expiry period as being your arrival time plus 1 hour. Arrive at 18:30 and the ticket will show 19:30; because you've only paid £1.20 for one hour and only £1 extra which doesn't take it up to the next hour.

How, therefore can one blame the attendants. If they have no ability to tell if someone arrived at 17:30 paid for 2 hours and then overran or if they arrived at 18:30. Possibly because the tickets issues have both the arrival time and amount paid displayed on them.

Yup in nice big letters 18:30 and 19:30 and underneath  £2.20. Guess they're not paid to think just to slap a notice on if the latter time has overrun.

How much is being spent on issuing these incorrect notices? How much in admin costs in responding to challenges? How much paid to the council when it shouldn't have been by those who thought they'd got it wrong?