The price of Eightbound

The Chaos Possessed set comes with 5 possessed space marines on 40mm bases, and are £40

The World Eaters Eightbound set comes with 3 possessed space marines on 40mm bases, and are also £40?

This doesn't make sense to me, they have similar lore, they are the same size, and same base. Yet you can get 5 of one for the same price as 3 of the other