[Xen-Soluce] Upgrade Coupons 2.1.3 Fix 2

I have a somewhat complicated user upgrade system which resulted in a couple of errors in the Upgrade Coupons addon. XenSoluce was very prompt in providing a solution to those. I also needed to extend the operation of the coupons and XenSoluce quickly provided a companion addon (Recurring Subscription) to make this work. I really can't say enough good things about both the addons and the support they provided to make this work for complicated conditions.