Seems like an aggro problem of your OT. Our DDs can go full blast, almost instantly. No 4 Renauds before Melee adds is not possible without stalling the fight. If you stall so long you will end in enrage.

We do it the follows: First add is grabbed by MT, Second Add is grabbed by OT and provoked then by MT and only the third add is tanked completely by OT. This way OT goes dps as well.