I have some questions about the below options: (On Carrera S/Cab)

Option code AT - Black full leather
What does this mean? Which parts are leather? Does this effect the seats? This is quite an expansive option, I really would like to know the difference between this option and the standard leather of the Carrera S.

Option code P78 - Sports Seats w/Full leather Int
Again, what does this w/Full leather Int means? It can't be full leather because option code P77 is Leather Sports Seats and it's more expensive than option P78???

Pretty confusing, I would appreciate any help.
Thanx!