There is a store screen based on
VPS_TEMPLATE with a single service plan included to the sales category published on that screen.
SINGLEPLAN_EDIT parameter is set to true. However the service plan is not put to the basket automatically, it is still required to add it manually.
The issue is caused by the bug with id #PBA-80736 ("SINGLEPLAN_EDIT is not implemented for screens based on VPS_TEMPLATE").
The issue is supposed to be fixed in OSA 7.2. Unless it is released store redirects can be used.