Nah, not really... the place I rent the 172SP from uses the 172S POH. I
don't think there is much difference in weights.

One other tidbit that I read just a little while ago was that the plane
initially took off with 3 girls + the CFII, then returned to drop one
of them off after she became ill. A father (I believe) of one of the
girls took her place. Perhaps this could be a contributing factor
toward the theory of fuel exhaustion. (pilot didn't check fuel after
the diversion).

Anyway, enough speculating on my part... hopefully the NTSB will be
able to determine what happened.