Nastalgia for EC NiM today, with problem question

Hi,



it feels like its been ages since Ive done EC at all, let alone nightmare, and today I had a feeling of nastalgia and set up a group on rep to tackle EC NiM, it was a pug and I was tanking it, had a couple issues reviewing some mechanics, but all in all, the group was pretty strong for a pug with quite high dps, well geared 55s, and some of their guilds I recognized as being good progressive raiding guilds, but despite that I had a question I just could not remember in regard to one mechanic that is bugging up to now, and that is of course Double Destruction that typically the tank places on 2 dps so the tank wont get obliterated by that debuff, so, everything seemed to go smoothly (eventually, took a couple wipes to review some old mechanics) and I was surprised by how fast both bosses went down. We downed Stormcaller and Firebrand on I think the third attempt, and timer was pressing for about an hour so didn't bother thinking about it at the time, DD during that run only appeared once her shield phase, we failed to get kephass down within the time for the title and other tank was pressed for time, so we called it after first attempt unfortunately.



Later I decided to setup another EC NiM on imp, this time with some pugs that weren't quite as skilled or geared as the group I put together on rep earlier. We wiped on Zorn and Toth first while clarifying some mechanics for one heal and couple dps that weren't quite familiar with even HM, but got them down the second time, but both enraged which was unfortunate.



In any case, we got to Firebrand and Stormcaller, and encountered miscommunication again and reviewing mechanics as an issue a couple times, but everyone finally understood, so we proceeded, but as I said, our dps was a LOT lower than the group on rep (in mostly all 69s as opposed to earlier 72s/78s) which I thought should have been adequate which i was proven wrong. This time again I was main tanking stormcaller, and DD comes up, move to dps etc, all seems to go well, oh but wait, something I did not expect, a second DD before defensive systems. I am adamant that DD only appeared once each shield/defensive systems phase in the group I was in on rep, and therefore, was a chore, but easy to deal with, but even though dealing with 2 DDs during each shield phase did become manageable, it was a real pain to deal with. Eventually we just gave up, I was told that the group under the firebrand shield were having some issues managing their aoes, and not both damaging the shield, and the one add in NiM that blows it up.



Ok, enough rambling, so, in any case, what was there the reason 2 DDs appeared during each shield phase on imp, keeping in mind dps was far lower on imp compared to that of reps group, and there was only 1 DD per shield phase making it easier to manage on rep?