User blog comment:FairyRaven/Fairy Tail Chapter 336: In Order to Live Today to the Fullest, Review and Commentary/@comment-77.195.192.216-20130622091133/@comment-7418318-20130622154139

I think he meant it the other way round. And for 400 years to pass in the real world, you'd need to spend a little under 4 and a half years in the CS Realm, if I'm not mistaken (since I'm tired and exhausted from my day so far, that's a good possibility though).