Non-annual Club Memership

I run a benchrest airgun league at San Juan Wildlife Federation in Farmington, NM. We have four 12 week leagues each year. We allow shooters to become members, but do not require membership in order to shoot. We charge a $20 league fee for each league. In return the league members receive a $4.00 discount on match fees. My problem with PractiScore Club Membership is finding a way to make club membership only good for 12 weeks instead of annually. Even though I have used the Custom area of Club Membership and specified the dates of the new 12 week league, members remain members past the end date of the old league. I attempt to solve that problem by deleting each member in the club membership, but when they request to be reinstated, they are not charged the fee for the new league and are still allowed to take the Membership discount. Perhaps I’m not using the proper procedure and if so, would like an explanation as to the proper way to support our league membership structure.
Thanks for your consideration.

@Steve_White
Because you do not require shooters to be members and your making the “membership” only the duration of the league there is no way to make the membership system work within your parameters.
My suggestion is to offer a discounted price choice for members. Many clubs do this and it still requires a bit of oversight but you only have 20 in the match and you probably know everyone, so it shouldn’t be a big deal. The just have to choose the member price option.