@Stryker1982 I think you're confused about terminology here.
MRV (also called MaRV) stands for Manoeuvring Reentey Vehicle. The key here is Manoeuvring. This means the warhead is seperated from the missile body and can be guided towards a target and can even make random manoeuvres (not dodge) in flight to confuse ABM. The Emad and Zolfaqar have an MRV. But the Shahab, Qiam, Ghadr, Scud etc. do not have MRVs, as the warhead remains attached to the missile, and don't have terminal guidance. The Fateh-110/313 have terminal guidance but the warhead does not seperate.
MIRV stands for Multiple Indepenently targetted Reentry Vehicles. This is the same game as the MRV, just there are multiple on 1 missile. For example, the SS-18 Satan has 10 MIRVs... all nuclear. It could have carried 40, but various treaties meant you could only carry 10 per missile. So it has 10 MIRVs and 30 decoys...
MIRVs are different submunition warheads. Those are basically cluster bombs mounted on missiles. Lots of tiny unguided bomblets.
@PeeD I think shahin is partially right. The Khorramshahr is too small to carry 3 large MIRVs - 650 kg as you say. Though I think it could carry 3 smaller MIRVs, more accurate. If used in a lofted trajectory, you've got 3 very accurate warheads coming down at very high speeds. Great for taking out Israeli/Saudi ABM.
The commander said the warheads are released after 1800 km. Just 200 km from the target. So I would presume, unlike the Zolfaqar, the warheads make a very steep dive toward the target.