Resource upgrade wizard fails to proceed with order placement showing the error message:
designProratedDowngradeOrdDet: resource lines have different amount value within period
This behaviour is confirmed as software-related issue #PBA-81582. It affects subscriptions with billing model "Before Subscription Period" that have a resource rate whose Recurring had been changed recently.
Contact your Technical Account Manager or Pooled Technical Associate Team at email@example.com to clarify the status of #PBA-81582.
To fix already affected subscription please contact Odin Technical Support.
It is also possible to get the mentioned error message for Change Orders. Detailed information can be found in KB #130768.