User blog comment:Catinthedark/Infobox level: killing the massive switches/@comment-3225604-20150705085205/@comment-4189499-20150706062316

The module shouldn't be transcluded on any page other than Difficulty level, however [Special:WhatLinksHere/Module:Difficulty_level?limit=500|WhatLinksHere]] is being decidedly less helpful than it usually is when it comes to transclusions and isn't differentiating between transclusions of the module itself and the transclusion of the module via the transclusion of the template. I think you could assume that Difficulty level is the only place the module is used though. I'll go ahead and lower the protection on that page.

Thanks for the explanation! Even if it isn't directly needed here, it's a good thing to know in the back of the mind for future projects. It's always good to work with both clarity and the convention!