ITP Models don't have to be recreated when a Field Set is changed. When an ITP Model is run, it collects the Field Sets that are used in the model directly from the ITP/MDK Repository. Field Sets are retrieved from the ITP/MDK Repository at the moment an ITP Model is run (runtime). If an object has no [published] revision, it will not be returned. Therefore, marking a Field Set revision as [published], indicates that the revision is 'accepted' to be used when the model is run.
Note
If the ITP/MDK Repository installation is upgraded from a version older than 3.5.10, by default the compatibility option "Handle Accepted revisions as Published" will be turned on. In this case, the status [accepted] takes over the role of the [published] status. For more information refer to the section Revisions used for production runs.
When an ITP Model is run from within the ITP/MDK Repository, it will retrieve the [in development] version of the Field Set if such a version is present and it is locked by the user who runs the model. Otherwise the model will retrieve the [current] revision.