Agree, take it in to get looked at. Dealers do not always prepare properly - I've had seriously over inflated tyres on at least two occasions, for example.
For all my other quibbles with my F10 520d M-Sport (with 19" wheels), ride comfort is not one of them. It's way better than my old e60 M-Sport and an e90 320d I had recently.
Haven't tried non M-Sport suspension on the f10; so cannot give any indication of comparison.
Note that when I sit on the back, I find it firmer than when in the drivers seat. Even over the same roads... Still good mind. Must be something to do with the seat cushioning???