If you are trying to place the order for two subscription regardless of plans (same plans or different plans), the order will fail to provision.
If you try to purchase two or more subscriptions together in a single order, you will get the below message at the end. Please follow the below workaround for buying two or more subscriptions.
We would request you to place two separate Sales Orders for the subscriptions. This is temporary while update our system to bring you new features.