BB30 bottom brackets

My new bike has a BB30 bottom bracket with an FSA crank fitted. I needed to make a few changes to the chain rings to took the crank off. It has a self extracting bolt which is handy.
When i refitted the crank back on the bike, i torqued up to 45nm (FSA recommends 45-55nm) but when i spin the crank it does not spin very freely. It was fine before i took it off and presuming that Connondale torqued it too FSA recommendations cant understand why its gone slightly stiff?? I loosened the crank and re-tightened to 40nm and still a little stiff but not as much. I then tried 38nm and all is fine. Could this cause a problem?
Now i know that there are great benifits from having a BB30 bottom bracket but i dont feel convinced.
Years ago i had a RaceFace crank which needed the bolt to be torqued up to around 45nm and i constantly had problems with over tightening and creaking and changed it for a Hollowtech II SLX crank and all my problems disappeared. I cant help thinking that the Hollowtech II design is still better that the bolt and torque system and that i would be better off getting some 24mm converters http://www.chainreactioncycles.com/Mode ... elID=46583 and fitting a Hollowtec II crank.

Anyone any thoughts please :?