AC is foolish not to offer upgrades from Flex/Latitude to PE. Many PE pax will be Altitude and try for an Exec. First upgrade, when those clear at the gate, you're leaving PE seats empty. If the flight is oversold, then you need to op-up Y-> PE. Why not get some e-credits out of it?

I suspect it's coming next year because it needs changes to their e-upgrade system as well. It's not only going from Y -> PE, but giving us an option to upgrade from Y -> J, and let them know if we'd be ok with a partial upgrade to PE.