From what I’ve gathered around the web, Ferrari originally proposed a rule change allowing teams to ‘trade’ windtunnel time, film days and straight-line tests for conventional testing time.
The 2014 rules would add upon existing time for windtunnel use, film days and straight-line tests.
It does seem rather vague, though. A usually well-informed commenter on a Dutch F1 site has said something akin to this being confirmed by Christian Horner to one of their journalists in an interview. That interview is yet to be published.