Probably bad wording[edit source]
"Skill total worlds Skill total worlds are worlds that are locked to accounts that do not meet the required Total level to enter. Free-to-play skill total worlds calculate total levels from free-to-play skills alone and do not acknowledge members skills, meaning a players require a cumulative total of 508 or 758 in free-to-play skills to enter those worlds."
This says that to enter a f2p 500 lvl world, a player must be 508 total levels of free to play skills. I think this is meant to say that 500 total in f2p skills. A player with lvl 1 in all p2p skills end up at 508 total - but it does not require 508 in f2p skills.