greatest interference play i ever heard
 

A fellow umpire gave me this scenario
scored tied,bottom of the 7th runners on 2nd and 3rd high fly ball hit to ss runner from 3rd base raises home, runner on 2nd base grabs ss as she is ready to catch fly ball (remember runner on 3rd touched home when interference accurs) would you let the winning run to score?

Dead ball on the interference, which is a batted ball. No action can occur as a result.

interference happened after the runner crossed home

No

On a batted ball!

Think to yourself here Andy. If SS had caught the fly ball, and had not been interfered with at all, and then had thrown to third on an appeal, what would you have had?

Doesn't matter.

remember fellow umps last base touched at the time of interference so runner on 3rd already touched home when inter ference occurs

Answer my previous question about the ball being caught. Do you care then that the runner has already crossed home? Or, will you honor the appeal?

Oh...also, for the play you stated in the OP, the information you provide here is totally irrelevant.

An out on the appeal
 

But that's not what happened in the OP. I would let the run score as home was the last base legally touched prior to the interference. The argument could be made that since he left early home was not "legally" touched. However, I would not interpret it that way because we are never to give away that a runner left early. This, in my opinion, is similar to assuming that a runner touched a base unless properly appealed. Then you rule on the appeal. So, until a valid appeal is made at third, I would score the run but wait to leave the field in order to give the defense a chance to appeal.

Sure it matters
 

You don't put the runner back on third. He touched home before the appeal. Score the run, but wait to leave the field to give the defense an opportunity to appeal the runner leaving early.

How is it irrelevant?
 

It is most certainly relevant as on any interference call, you put runners back to the last base touched.

In my old 2008 ASA rule book:

and

R2 would have been the "immediate" previous runner, no? No run scores.

EDIT: Oops, 8.2.K is a "thrown" ball. Hmmm...

The OP didn't include the number of outs
 

Also, the interference was on batted ball, not a thrown ball. So 8.2.K doesn't apply. The exception to 8.7J-L does apply. If the interference prevents the fielder from catching a routine fly ball, fair or foul, with ordinary effort, the batter is also out.

So if there were two outs, then the run would not score.