Recently I've come across one post which I think you might find interesting. Someone may take a steaming dump all over it, however it clarified some of my questions. 
https://yunclillos.com/essay/who-can-do-a-consumer-sciences-essay-single-spaced-mla-american-professional
http://www.gerl.org/paper/where-to-order-an-racism-paper-mla-double-spaced-writing-quality