I fly the F-27 myself.
Couple things. Bringing up the flaps after landing will reduce the lift significantly, even if you have an aircraft equiped with spoilers. The lower part of the wing will still produce an upward force (lift) which is higher with flaps extended (Action=reaction). Maximum braking is only possible with as high as possible weight on the wheels. Therefor reducing flaps after landing to reduce the landing roll is a possibilty.
However, by bringing up the flaps you also decrease the aerodynamic breaking.
My opinion: I don't think it has a noticable effect on the landing roll regardsless of what procedure you use.
By the way, it is not a SOP in our company to retract the flaps after landing in order to reduce the landing roll.
Cheers, and happy landings!!