Penalty on Try

[lds7199]

Is there any difference in the enforcement of penalties during a try. The reason I ask is because we had a facemask penalty on B behind the line of scrimmage on a two point try. The WH instructed me to go back to the original line of scrimmage and mark off half the distance. I thought that the penalty for face mask was from the end of the run (in this case, the 9 yard line). When I asked him why we didn't enforce from the 9, he said that the penalty enforcement is different on a try. I have looked all through the rulebook/casebook and can find no mention of penalties being enforced differently on tries. Where should this face mask penalty have been enforced from?