Yes sometimes discounted FC is cheaper than Y fares.

Why would someone still by the Y? Well most companies have a policies against FC tickets as a blanket rule. So if this were the case, you couldn't by the cheaper FC seat but you could buy the more expensive but legal Y seat, then use your elite status to get upgraded.

You get the FC seat you wanted, NW get the most money out of it, you company is paying for a coach seat...All are happy....ok maybe not the accountant....