Firstly, it's not complaining. Secondly, it's not a matter of quality. I'll expand on the example and hope you understand.

When I sort my DVDs, I put them in Film and TV sections, then sort them alphabetically. The numbered FFs would be TV series, whereas the MMOs are films. That's the only issue I take with having the MMOs as part of the standard numbered series; it doesn't conform to my rules of categorisation. xD