Everyone nailed all the questions just missed one detail about that NPC talking about level 50 and all that jazz. It's just in reference to the "armoury bonus". This bonus is active for all dow/dom jobs that are lower level than your highest class and it grants those lower level jobs a xp bonus of 50%. The NPC is just referencing the previous maximum level but again this bonus works for lower level jobs. So if your highest level is 30, all jobs lower will get 50% more xp