I don't see how you could have accidentally missed this part in your reference:
I didn't miss it. Nor did I miss this bit:
"In some of the recent cases, the hostile fire was carefully planned. That is, multiple machine-guns, including at least one heavy (12.7mm or larger) machine-gun, were placed along a route used by helicopters, and fired in a coordinated matter. This tactic is called "flak trap," and dates back to World War II (or earlier). The enemy has also been using portable surface-to-air missiles since 2003, including more modern models, like the SA-16 (which is similar to the American Stinger.) American helicopters are equipped with missile detection and defense (flare dispensers) equipment. Thus
the most dangerous anti-aircraft weapon is the machine-gun, not the missile.
American helicopter pilots have been dealing with the risk of deliberate flak traps since 2003, and the
current losses are partly the result in getting sloppy. That means flying the same routes too often, and too predictably, makes it easier for these ambushes to work." (emphasis mine)
I'm well aware of the entire contents of the link I posted. If you drew different conclusions from that link than I did, it's not because I missed any of it or didn't understand it.
From your source:
"Lawrence DiRita, a Pentagon spokesman, said there was no reason to believe such a device was used to bring down any of the three helicopters that have crashed since January 8."
In other words, there's no reason to believe this new technique has actually been successful.
Helicopters getting shot down are actually infrequent events. Statistics of small numbers can make it seem like the rate is suddenly going up, but all that's really happened is you got a cluster at one time but the overall trend can still be going down. Sort of like perceptions about shark attacks: a few in a row can make it look like an epidemic.