I called on 1/5, to book such an international, a few minutes before Delta sent me the e-mail regarding the changes, and the agent immediately told me about the 5$ fee. What we did to avoid the fee, was to ask the agent about the Z-class inventory on the flights we were interested in, which was free of charge. I then hung up the phone, booked online in M, and called again as soon as the tickets were issued to upgrade to Z, again free of charge.

No 5$ fee was charged and I was told that there will be no charge when handing in the PMUs before the flight. What I wonder though, is whether I will get the bonus miles for booking online. They have not posted yet ...