Checking my notes, my last four lagers with S-189 came in at an average of 78% apparent attenuation. My Oktoberfest came in a little lower than my expectations at 1.010. However, once carbonated, like santoch mentioned, the mouthfeel and the perception of maltiness was right on.
I'm pretty sure that my experience with S-189 is typical: it is said to enhance maltiness. And, all of my lagers were within one point of AA. Your AA seems a bit higher, but it's only a number.
Wait til it's ready to drink, forget the numbers, and see how you like it.