The airplane as at 325' +/-25'. The helicopter hit it. So we know with certainty what elevation the helicopter was.
And that was well above where the helicopter was supposed to be.
A caution about deviating from specifications, that applies most anywhere:
If the deviation does not cause immediate catastrophe (IOW, if you 'get away' with it), it will become part of an accepted practice, because it caused no harm. Future deviations will not be restrained by the limits of former deviations from spec, but will be added on to that new 'normal', because that 'new normal' did not produce catastrophic results. In practice, actions will eventually be well out of spec until there is a catastrophic result. That applies in ANY industry, from farming to the oil patch and beyond.
It's why safety hands and others of their ilk are often thought to be 'anal' for being such sticklers for meeting specifications first time, every time, but they understand that any culture that plays fast and loose, even a little bit, with the program will eventually have a disaster.
Little deviations can add up (sometimes they cancel each other out, other times they build on each other and all the holes line up in the Swiss cheese), and there will be a catastrophe.
Any other time, a few seconds either way, and there would have been no collision (just a close call or nothing), regardless of the helicopter being above its assigned altitude limits, because it would have passed through airspace not occupied by a plane on short final. IMHO, the ATC was not clear and specific in notifying both aircraft of the potential threat as well, but had the Helicopter been in its assigned flight corridor, there would have been no collision.
