Every sold merchandise items can be seen by a multi-users when they have access to the related offers.
Go to "Settings > Multi-User Access", select the relevant multi-user via email address and click on the pen under "Actions" to go to the settings. Under "Grant this user access to > User actions", you can select the function "Merchandising". When you activate this function, the multi-user will be able to see sold merchandise items in the booking overview.
Go to "Settings > Multi-User Access", select the relevant multi-user via email address and click on the pen under "Actions" to go to the settings. Under "Grant this user access to > User actions", you can select the function "Merchandising". When you activate this function, the multi-user will be able to see sold merchandise items in the booking overview.
Result
Under "Booking> Bookings", search for your Book offer ID and check your products as a Multi User
Note
For all product that Multi User has access, sold add-ons will be shown in Booking dashboard