Are they only going to repair half the Skyway? I'm guessing, when this project is completed, they'll have to close the southbound lanes for similar repairs.
My guess is that once they're done repairing half, they'll shift the southbound traffic to the newly repaired lanes so they can repair the other half. That way they only need one diversion/detour plan for the whole project. Hopefully they can repair the whole thing in the 2 years, although I'll bet it takes at least 3.