What date is that POH? The POH for ours (PA28-180 1972) specifically states the only takeoff procedure is to accelerate to the "takeoff safety speed" 68KIAS and initiate the liftoff. "This speed applies to all weights and altitudes."
I've heard the technique you describe recommended but it's not in our POH.
tmmorris I think that was the only technique scheduled performance in the original (CAA) Flight Manuals and is still included as a CAA annexe to the later (FAA) POHs. One point to note is that FAA figures are not factored whereas CAA usually are (i.e. X 1.33 for take off, 1.43 for landing and HWC 50%, TWC 150%).