Sorry but pitch is the angle of blades and predetermine by manufacturer to match the motor. A couple of suggestions. If the fan is new I'd return for another model with low profile light kit(if available). Also in some cases a four blade moves air better. In fact some of the best and most expensive fans are four blades. Again flush mounts especially low cost normally just are not efficient. The fact your others are flush mount and blow fine is great and it can easily be the design,room size,ceiling height,etc which can be factors.