I too was little confused about the admission costs from reading the club magazine but other club members from my local area clarified things. Have now booked two tickets and looking forward to the event. Will there be parking on the banked part of the circuit again? - I’ll make sure my handbrake is fully operational 
I’m quite new to the MX-5 OC but think it represents pretty good value - lots of events with our local club, national events like this plus a bi-monthly magazine so plenty going on for us MX-5 enthusiasts.