So you must be paying ACO membership. Which struck me as a good deal a couple of years back as it allows up to 6 (I think) camping passes and entry tickets, and if you required the full amount for your party you saved money before you even started (ACO membership being somewhere around £50).
Then you get the added benefits - (somewhat limited) breakdown cover in France, 10% discount on official ACO merchandise and access to the ACO members bar and facilities (for you and your family - strange how for these purposes only (!!) my wife is male, about the same age as me, and so are my kids...still, we've never been refused entry)
However, membership gives you no preferential treatment when it comes to ordering your tickets apart from the price.