Thank You all for the answers so far.
Well, it seems that - following Novice's suggestion - if we were to have these ships kept separately ("cargo+some passengers" at "Cargo" and "passengers+substantial cargo" at "Passengers") then somebody would have to check them all, one by one.
Thankfully, so far the problem didn't occured with the MARAD ships. Of course, in this case the belonging to either C or P series could be indeed a decisive factor.
Problem we have here is that ships in question need to be classified either as Cargo or Passenger, while the (alternatively) "Passenger and Cargo" or "Cargo and Passenger" description are inserted in sub-type.
Speaking of Hurtigruten - I finished uploading Norway earlier today and put large part of them into Passenger TYPE as "Coastal Service Vessel" SUB-TYPE (though some are in the Ro-Ro's - well, You can check for Yourself - in fact I'd be happy if You did and check if everything's ok there).