Marketplace search and filter options aren't working well

I'm not too sure if this is a bug or a regular feature. Browsing through Marketplace, I've noticed that when you search for 'World maps' or 'Adventure maps' it will show you skins. Then there are times where I say 'search ALL maps' and the result will say 400, but instead only shows you 10. Even if I add a filter like rated highest to lowest, it will only show me a handful instead of the full 400. Makes it very hard to find things when the search and the filters aren't doing what they are made for. Is this a bug?