The idea behind a price change is to encourgae earlier renewal or purchase to advance the cash received, or peoples circumstances changing, or people having too long to think about what a shit show it is.
From a business perspective getting the money in earlier is always a good idea to remove risk but also benefit from interest etc, especially in the low season for income when no matches are being played.
I have used something similar in businesses I have been a finance leader to encourgae customers to pay quicker, say normal terms are 60 days but offer a cash discount if they pay in 15 days (2%) or 30 days (1%).
The problem with a football club, esepcially one like ours, is that disposable income is not massive for most and in the summer with holidays, kids off school etc, it can get eaten up a lot quicker so having 300-500 quid to spend is tough many at this time of the year, especially if trying to justify it to the better half at the minute!