To those of you quoting QRH Ldg Dists... In our Ops, these are for "non-normals" only... and for consultation "in flight". The Manual Land tables further state they assume "Max Manual Braking" and "Max Reverse" and are unfactored. They go on to say that an appropriate factor should be added, and that "50% is a conservative factor".
For planning purposes, there is a Performance Manual distance, and it is this distance that is amended by the MEL. I again state I believe that 1 Rev U/S would affect the "Wet" landing distance using the planning criteria.