Well remember the first day to send out applications is June 1st, but secondaries don't start coming until right after 4th of July. Last year it was July 6th. I'll ask REL to find out when they come out when it gets to be closer to June. But at any rate......
This means, that you won't be late to turn in your application if you wait til score release in June. So I'd wait for your April scores. Now if they don't turn out to be what you wanted and you think you'll be retaking, you will just check the box that says taking August MCAT.
At this point, you may still send in your application so that they have reviewed over everything else and may begin secondaries despite of the MCAT score not being released yet. Here at USF, what REL does is as follows:
He will send applicants an email saying to confirm that they meet the minimum requirements. If they respond with the fact that they do meet these requirements he'll give you a secondary. Even if you haven't gotten scores yet, you just indicate that you have met the requirements pending and they'll give you the secondary. If after score release you don't meet the requirements they'll disqualify you, but if you have met it, then you are ahead of the ball game by having turned in everything early.
That's the best I can do t resummarize why you should still submit things early.