It's a little more than that. From AAPL's perspective they sell a product now that they charge $1.00 per song. That song can be copied as many times as the person wants. If they put MM5 on the Itunes download the people will be restricted to only be able to copy it a few times or even none.
So the problem is can they sell it for the same price? It's now less valuable because you are restricted on the number of copies. So they may lose more than the the cost of MM5. Who pays for the MM5? I think the Labels should, and AAPL probably agrees. Their argument is that the CD retail store doesn't have to pay for MM5 (at least directly).
I personally think they could still sell for $1.00. Also the positive logic is that if friends can't just "share" after one friend downloads the song then the Itunes sales may increase.
So they are looking at both sides of the coin. And probably trying to negotiate the best deal.