The technical system for distributing the grace period DACs has a limitation that it can only be used once per account. If you have multiple copies of a product that qualifiy for the grace period upgrade, I’m afraid you’ll have to contact our support team who will be able to help you. As you might imagine they’re quite busy at the moment, so please be patient!
Steinberg Licensing itself can handle multiple quantities of the same product in your account. (The previous limitation has been fixed now)