I got an e-mail a couple of days ago headed "Check out your new standard package". One of the things was Exclusive Loyalty Discount (not sure how it can be exclusive when FindMyPast for one does the same thing!), which states
You have to renew within 1 month of your expiry date to receive your 20% discount.
so as Pootle says, you can get the discount up to 1 month after the expiry date.
What is interesting is that there is now FREE access to non indexed birth records, without having to buy credits, but you still have to search through the list to find your own ancestor, so FreeBMD is much easier.
Lizzie