Originally Posted by
jrkmsp
It's this. Delta couldn't sell both, but with the fare reclassing they just went through, it can now sell C+ and PS on the same planes. The 359s and refit 777s have extra space in Y while they awaited being able to put the C+ back in. It's just a manner of sliding the seats around to their new designated spacing and slapping some new seat covers on. Should be done on all the 359s and 777s sometime in the next year or so.
As noted above, it's actually more complicated than that. They have to move the reading lights and air gaspers and flight attendant call buttons