Quite interesting thread.
Could not really make up what really happened.
I assumed that given the load and hight it should not run out of power (assuming it was a II) Personnaly had many VRS's in that case but no low RRPM.
So perhaps it is as Nick says combined with InducedDrag's remark that as she approached hover she got nervous and frooze the trottle when starting to pull the collective this being the reason for lack of power.
d3