What type of skiing are you doing? Whats your level? Who is the shumck that told you to buy a 18 din all metal binding when your only an advanced skier?
The fact that your asking if you need a FKS is proof that you dont need it. Unless your a super unknown ripper in NJ that hit 60 ft cliffs on a daily basis or hitting 80 money booters, you dont need that burly of a binding. Period.
If you have already mounted a ski with it, you should think about taking it off and putting something else on. If you haven't mounted it return it or sell it. you dont need something that burly.
But like I said I dont know you. Maybe you are a pro park rider who needs a all metal binding with it cranked to 18 din.
From what I'm hearing you should consider getting something different. Here are two bindings you should consider.
http://www.evo.com/alpine-ski-bindings/rossignol-axial2-120-l-90mm-brakes.aspx
http://www.evo.com/alpine-ski-bindings/salomon-z12-ti-90mm-brakes.aspx
If you want somthing a little more Burly then these two go to the Salomon STH 12 Driver. Same thing as above but lot more metal.