It's interesting the way you said that... he was looking for scientist Locke... I have a theory about different timelines effecting pregnancies on the island. Maybe Richard is travelling to different timelines testing Locke in each one to find a certain one. Maybe the young Locke we saw Richard testing isn't the same Locke who landed on the island.

I'm also thinking that with different timelines and some of the theories I've read about the bearings for getting to and leaving the island being inconsistant... Maybe the bearings to get to the island are different depending on the timeline and maybe if you leave by different bearings you get to a different timeline. Ben may have sent Micheal to a certain timeline so he would know where to find him. It may also be a timeline in which Micheal is dead (killed himself maybe?) and therefore cannot die there again... I'm getting off topic...