Obstruction, when judgment is made on protection

[Dakota]

Here is a situation posted on another board:

Runners on first and second, double steal, catcher overthrows third and runner advancing from second to third scores. Runner from first gets interfered with by shorstop on way to third and umpire signals obstuction, ball kicks around in left field and obstructed runner rounds third and continues home,Runner called out on a bang bang play at the plate. Is the call correct?

This seems like a better board to raise the issue (again, I know) of when to make the judgment on protection and whether it can be modified by later playing action. Here is the answer I posted on the other board:

Speaking ASA ruling from NUS. (This is not a quote but my understanding. Mike may want to clarify further or correct.)

The ASA NUS has instructed umpires they are to make the judgment of what base the runner would have achieved had there been no obstruction at the time of the obstruction and not have that judgment affected by subsequent play action.

The ball kicking around in the outfield was, presumably, a defensive misplay that occurred after the obstruction and after the umpire had formed his judgment on protection of the runner, presumably to 3rd base.

The runner trying to score as a result of the misplay was her choice, and she is no longer protected.

Assuming my understanding of the interp from the NUS is correct, I really have a hard time with this one. In the play described, it seems to me that unless the runner stopped on 3rd and then decided to proceed, it is clear that as the play actually unfolded the runner would have scored had there been no obstruction.

Is my description of the NUS interp correct?

Do you agree with this interp as being proper given the intent of the obs rule?

Assuming the answer to my question #1 is YES, then MY answer to question #2 is no.