Mr Indoorsman

I already have a Bonus cache that is a Letterbox and have just had another refused to be published as such, seemingly due to the new attribute of 'bonus cache' being introduced. The reviewer is just applying the rules but I'm not sure why an attribute being created would necessitate that change of treatment? Can someone from Head Office or similar please explain the logic behind this. The existing Groundspeak rules on 'if it has a stamp it's a letterbox' seemed to have been voided here for some reason. Pretty confused.