There will always be differences of opinion on this type of subject. You have what's in the manuals and then you have what works in the real world. It is the difference between procedure and technique.
My personal technique after 22,000 hours of 737 flying (-100,-200,-300,-500 &-700) is to trim up a little just crossing the threshold followed by a slight push on the yoke at about 2-3 feet. It makes for a soft touchdown and cuts down on the floating that may result with just trim/flare. If your manual prohibits this technique then you will just have to develop something that works for you within the confines of your company's procedure.
In regards to those who say just blindly follow what the engineers who designed it tell you, I say, they are engineers and there is no substitute for an experienced PILOT.