Season Pass Question re: Cedar Fair Sites

Hello,

We typically purchase four Six Flags (2nd tier) season passes for our family. This summer, we are thinking about going to Worlds of Fun (and maybe King's Island.) It would seem that it might be best to get the All Park add-on (for I believe $125/ticket.)

When I read on the website, I see that it appears this plan would work for King's Island, Cedar Point, and lots of others but does not specifically mention Worlds of Fun.

Does anyone know if that isn't included or if there is a special circumstance with that? Thanks!