I think that Do 328 (Both version props and jet) isn't really profitable on normal route. Even for flight with 20 or less pax you need two pilot, a cabin crew, handling and parking fees (usually not proportional with the pax number).
This kind of planes are profitable only on route with state aid for connecting pourpouse or on business route where peope can pay more for a point to point services.
In italy there where Four airlines using Do 328: Gandalf, who is under bankaurpcy, Minerva , who has suspended all his flight in dicember, Federico II
who has suspended his flight last year and Air Valee, a little niche airlines still flying.