While we're having a nice calm chat about it, why don't I throw some gas on this fire. Actually, this is just info, much of which is of PURE academic interest. If you know better, call BS and provide your data.
So, there's a report out that's being claimed as authentic which says 113mrad of up was necessary. FYI, that would be like aiming 1100ft over the target with buckhorn type iron sights. Great googly moogly, right?
My own estimation is closer to 85mrad of up. That report I mentioned also claims they used a very specific API round which is identical, fortunately, to the MK211 Raufoss whose ballistics are very well known. I did the math on that load and no combination of reasonable MV and atmospheric factors I could twist together allowed for anything like that distance and that DOPE to coexist. In fact I couldn't get it to that distance above 300fps at all, when I got it there it needed from 40% more to several times that amount of up and I played with some really thin atmospherics just to get it there at 300fps which is where I start calling the line between simply dangerous and potentially lethal on an object of that mass and density. So, I'm calling 100% BS on that specific report (if you really want the link I'll dig it out, pm me, feeling lazy right now).
There are of course a number of conflicting reports from guys that know guys that know this other guy that etc... that specifies that they used the 750gn A-Max sniper load that I spec'd though at a marginally higher (2 digits) velocity. It is likely that because of dynamic destabilization inside the transonic zone that the bullets were becoming increasingly unstable after 2.2km which would manifest itself as additional drag from the shooters point of view so it would be entirely possible to need to dial up radically higher and very suddenly; to say 113mrad, with the A-Max load to hit at 3.5km. It would also be still going over 500fps which is definitely lethal. It's also equally possible that a scenario unlike anything bandied about so far occurred, nobody knows squat and Rex and I basically used our combined knowledge to take a good swing at explaining that without the incredible skill and teamwork brought to bear that day combined with tons of luck and quite a few rounds of ammo it would have never happened.
To the question about shooting from somewhere high up... the highest structure of any kind in Iraq is around 1600ft tall, it's a radio/tv mast of some sort. The tallest building there is about 50 stories IIRC (there are no tall buildings of any useful height at all in Afghanistan that I can find record of). From the radio mast the angle of fire would be about -8 degrees which brings the angle cosine to over .99 (so over 99% of the up is still needed). If from the tallest building it would have been about -1.6deg (over 99.99% of up still needed). Both of which are seriously close to level as you can see by the True Range vs Actual Horizontal Range numbers that come out of those percentages. It wouldn't matter in the slightest because the target is just too far away to have a structure tall enough to matter. For example, at 20 degrees angle of fire the drop would be equal to a flat shot at around 2400, much more inside the rifles range. To do that against a target at 3500m distance you'd have to take a shot from the top of a building 30% taller than the Burj Khalifa. You'll only encounter elevation really mattering at somewhat more pedestrian ranges because Pythagoras is a total jerk.