According to current functionality, if a Customer places 2 Scheduled orders at various times for the same subscription and they aren't aware that 2 orders exist, only the most recent Scheduled order will be processed by Microsoft , when the renewal date arrives for the subscription.
This potentialy can lead to a situation, where the customer is expecting for both orders to be processed and miss out on the renewal date for 1 of the orders, as they expect both order to be processed.
We need to think of a solution, where Customers are informed that there is already an existing Scheduled order placed for the subscription.
There are two suggestions that could implemented to mitigate this issue:
add a disclaimer that scheduling a change will overwrite the previously set order change;
have a visibility on already existing scheduled changes for a subscription