The description of the rule making process given at the FCC site [1] says that "The Final Rule. After the comment period closes and the Commission has reviewed and analyzed the comments received, we decide whether to proceed with the rulemaking we proposed, issue a new or modified proposal, or take no action on the proposal".

This makes it sound like the final rule must be the rule that was proposed and commented on, which would mean we've looped back to issuing a new proposal.

[1] http://www.fcc.gov/encyclopedia/rulemaking-process-fcc#q6