I don't believe the other Preferred numbers request that you enter your DM number. Certainly not the Gold or Platinum lines (unless you choose the option for Alan). Never called the general number, so I don't know about that.

FWIW I recently got an automated call regarding a flight cancellation and the number that was left on my voicemail was actually the CP number. I called but didn't feel like figuring out my alphanumberic DM number on my smartphone keypad so I hung up and just called the Plat line. I have no idea if it would have just routed me to the PP line if I had entered my number.