Last year, during the re-alignment kerfuffle, there was lots of talk about "value added"--how much $$$ a candidate school would bring via brand (Nebraska) and/or market (Missouri with KC and StL). It's interesting how much value SU and Pitt have brought to the ACC; not for either of those reasons, but because the expansion allows the ACC to re-open a contract in which they were seriously short-changed.
I would think they are trying to negotiate with FSU still in the fold. Their previous agreement had a reopener if the conference changed by two teams. So if they negotiate now they get bang for the Buck and losing only FSU doesn't cause the contract to reopen.