Yes, and if you play against a team with an AML and you have an MR you can put a blue arrow on the MR to try to get him to track back but he might not make it and won't do the same job as a DMR being there to specifically mark him....... but he will do a better job than an MR without an arrow.
But I'm not saying another way of thinking about it is wrong.....this is just the way I think about it because it makes more sense to me. But sense, logic and this game could be 'strangers' fated never to meet. XD