The point is trying to make it better for sellers, while still maintaining revenue for the club. Sellers are more likely to bring more/nicer stuff if they know they only have to sell it at a price they believe is fair.
Sellers can now determine their price based on what the club fee would be. For instance if you know that you want $8 for a bag of fish, and the club split is 20%, then you'd need to set your bag price at $10, and you'd still get your $8, and the club makes some money. In this sense, the club makes the same amount as if your bag sold in the auction for $2, but this time you're actually happy because you're making some money. Because of that, maybe you bring several of those bags instead of 1, and both you and the club make more money.
Of course that only works if enough people come who want to buy fish and that sellers sell what they bring, but it will be trial and error for everyone. But eventually if word gets out that the quality and quantity of fish available at the meeting improves, maybe more people start coming again.
Also, just because I can get a bag of fish in the auction for $2 doesn't mean I wouldn't spend $10 on it from the person who brought it, but sometimes people just aren't bidding. I've ended up with bags of fish I didn't plan to buy simply because I was 'starting' the bid and nobody else countered. I've also bid on fish that I expected to go much higher than it actually did. I've seen bags of BNP go for $2, but if I found a bag of them for $5 or $10 tomorrow I still might consider buying it. Plus you might find stuff tomorrow that you'd never see in an auction because the people won't bring it knowing they wouldn't go for an appropriate value. I'm sure Josh will have stuff I'm interested in that doesn't go to auction, but I still might end up buying.
Anyway, we figure this is worth trying, and we're looking forward to hearing feedback from everyone after the meeting. We'll never know if it works better if we don't try though. And we're always trying to figure out how to get more people to the meetings, but there doesn't seem to be an easy solution, and its a common problem for all clubs in the area, we actually seem to be one of the more highly attended clubs.