I am aware that you can get special Level 55 rings once you have completed all of the class and job quests of a warrior or magic class by speaking with Jonathas. However, while I have gotten the rings for the Lancer/Dragoon and the Rogue/Ninja, when speaking with Jonathas after completing Conjurer/White Mage and Gladiator/Paladin, he does not give me rings for having completed those jobs and their respective quests.

Is it not possible to obtain rings for every warrior/magic class and job? If it is possible, then why will Jonathas not give me rings for both White Mage and Paladin?