Question on ASA RS #33

[Manny A]

Here's what the ASA Rules Supplement on Interference says when it comes to a runner hindering a fielder on a batted foul fly:

If interference occurs by the runner on a foul fly ball not caught but, in the umpire's judgment, could have been caught with ordinary effort had interference not occurred, the runner is out and the batter is also out. If, in the judgment of the umpire, the foul fly ball could not have been caught with ordinary effort, a strike is called, the ball is dead, and the batter remains at bat.

So, if the ball could not have been caught with ordinary effort, would we still rule the runner out? The RS really doesn't say. It seems to me if a foul fly is judged uncatchable, then there is no interference since the fielder could not make a play. Or do we give the fielder the maximum benefit of the doubt that she might have made the catch with extraordinary effort?