Wrong! Mr Boeing has taken the use of the spoilers into his performance calculations for takeoff
It all depends how much spoiler is applied. The operation of spoilers creates drag. Drag increases as the square of the velocity. That is why there is a marked deceleration immediately on touch down as spoilers are automatically deployed. Same principle applies at higher speed during take off run. Nearing rotation speed spoiler operation drag is significant if too much applied. Boeing stated in an earlier edition of the FCTM that I have, that the take off distance increases with inappropriate use of aileron/spoiler use during a cross wind take off. This in turn makes V1 useless.