In terms of the damage actually done it was trivial. Israel "won" that exchange and the US is trying to convince Israel to take the win and not respond.

In terms of the number of mutitions fired it appeared that it could have been more than proportional if not defended against, and that is undoubtedly the reasoning Israel will use. 

 Good analysis in general. I’m not a fan of Israel, but I also have contempt for the sociopaths who run Iran. I doubt they were deliberately attempting proportionality and just underestimated that capabilities of the air defense alliance and its equipment. However, I do hope Israel will not respond!