If you go to www.fordvehicles.com->Crossovers->Edge->Models and do a compare of the SEL and Limited you'll see that memory seats are only available on the Limited and not on the SEL. NEVER believe ANYTHING the dealer tells you - always verify yourself anything that you really care about.
And if you follow the link I gave you then you will see the reference to memory seats on page 149, even if it's not in your copy for some reason.