Originally Posted by CDKing

Are you refrring to the ability up upgrade to business/First with cash? yes in that case the F seats will disappear as upgrades are processed

OP is referring to getting an economy plus seat which is not technically an upgrade as its the same cabin just a better seat.

Once 24 hours comes they will disappear as the Silvers now get them for free and those without seat assignments get auto assigned to E+ when E- runs out or ran out at booking