That seems to be the answer, the aircraft we flew was a SFP B737, in the MEL for our normal 737's the penalty is not there.
However, I cannot find any reference in the manuals (FCOM/AFM) about this feature.. The only comment is : "Following an all flaps up (no flap) landing, the SPEED BRAKE lever will not move beyond the FLIGHT DETENT and the spoilers will not fully deploy." This comment does not affect the takeoff or RTO. Anyone can point me to the correct reference in the manual?