Have you had a chance to answer the previous question?
Yes, after a few months we finally found the answer. Sadly, Mike is on vacations right now so I'm afraid we are not able to provide the answer at this point.
Registrations Timespan Policy
When you add a product, a service or a managed cloud resource to your cart, it will create a Cart Registration. This registrations will be available for you to customize your order preferences and place orders or provisioning requests in just a click. Cart registrations for your Alliance ID Tenant Cart won't be deleted until the first day of each month.