It's always better to go for the furthest date anyways, as Obs will start the push to induce you after a certain time over your EDD so if you have an earlier one, baby just might not be ready yet. Ovulation is more accurate if you know when it was, scan dates are not the best either and only 5% of babes come on their EDD! The majority come in the 2 weeks before and 2 weeks after the EDD.