You could try calling in and setting up the cancellation now before your promotion ends. I think you may then be able to get a yearly retention deal. Aim for the $89.94 + tax.
I had a month left before I renewed and I got the credit towards the $89.94 deal. So maybe your current credit would count towards it.
This is what I did to get it with about 10 days left in old plan see my earlier post