Ohhh sorry for the confusion. The setting was meant for portal engine sites. So, in the MVC app, you need to get the values of the document meta data fields as you are getting values for any other fields and format them as you need. That setting is not available. Or, you would need to use the settings API to get its value, process it and then set the meta data accordingly using custom code.
Or, upgrade to Kentico 13 where were made changes in this regards and the setting is taken into account when using the API I mentioned in my first post.