Every report I've read said they couldn't.
Only thing I was thinking about was if losing say Carr, Ferguson, and Paulk would be "back countable", but I don't think that is how it works. Those scholarships were used for those years/classes and you can't act as though they were not.
You do have to remember that all the recruiting services were talking about CBJ using GS's and BS's last class so he could take more, and he didn't. Maybe the signing 27-28 number is just guessing at this point with little to nothing to support it. If you can't back count the spots, I don't see how you can sign more than the SEC limit.
If there are a couple commitments who have agreed to GS, maybe that is in play. Just have to hope if they are told last minute it's GS or nothing, we don't lose them.