Ms McSweeney said the Court of Inquiry's findings did not come as any great surprise to her, but it had "dotted i's and crossed t's".
"The thing we take the most comfort from is that Luke was in exactly the right place, he wanted to be there, and he was very proud of the work that they had done."
Six soldiers were injured during the first incident at Baghak, with two most likely hit by friendly fire, the inquiry found.
It said friendly fire incidents were understandable but not inevitable against the "fog of war" backdrop.
"It must be noted that the response and actions of those involved on the day, under such intense insurgent fire, nonetheless overall demonstrated the finest qualities of soldiering."
Lance Corporals Pralli Durrer and Rory Malone were killed by insurgent bullets during that incident when the Provisional Reconstruction Team (PRT) went to the aid of ambushed Afghan colleagues.
The second incident considered by the inquiry was the attack on New Zealand soldiers when a humvee ran over an IED, killing Lance Corporal Jacinda Baker, Private Richard Harris and Corporal Luke Tamatea.
Chief of Army Major General Dave Gawn said all three died instantly when their vehicle was destroyed by the explosive made up of "50 pounds" of homemade explosives.
The bodies were flown to Christchurch on different flights where, during a pathology examination, a live grenade and two 9mm rounds were found on one of the bodies.
The injuries sustained by the soldiers were so traumatic that the fist-sized grenade was not discovered, despite uniforms being patted down.
Metal detectors also failed to detect the weapon.
"The families were shocked - I was shocked," Major General Gawn said.
Chief of Defence Force Lieutenant General Rhys Jones said the time when most people were put at risk by the grenade was while the remains were being flown back to the country on three different flights.
Former army chief Major-General Lou Gardiner told Radio New Zealand the training of Kiwi troops was focused too heavily on single patrols rather than several fighting together.
"Most of the training was geared around single patrols. This situation is a lot more complex because one Kiwi team went out and then two other teams joined them and then a fourth team joined them," he said.
"That is quite a complex arrangement which, certainly four years ago when I was chief of the Army, we didn't anticipate getting together in four teams like that and confronting a combat situation."