Did some video comparisons, I saw him do it up to 5 times on older hardware:
https://youtu.be/a8KOlqhdLkY
So I assume 6 should also be possible. He does more depending on his damage-percentage iirc.
The AI change is probably a thing people are imagining with NG2 since nobody is used to that game running at max speed. Like most games it probably ties its agression to its FPS, which is a lot more stable now. It isn't as big of a change as let's say with Vanquish after it made the jump from 30 to 60fps.
http://www.stingermagazine.com - articles on the action genre's best.
https://www.youtube.com/channel/UC09UqeY80WzoWMnxRkL4Tkw - challenge runs.