seiasce 7-02 unbalanced snow on a gable roof

huangyhg

seiasce 7-02 unbalanced snow on a gable roof
when w < 20' section 7.6.1 requires the use of an  unbalanced snow load equal to 1.5ps/ce.  in "snow loads a guide to the use & understanding of the snow load provisions of asce 7-02" published by asce table vi-2 gives values less than 1.5ps/ce.
for example w< 20', 8/12 slope, ct=1.1 the unbalanced snow is shown as 1.16pg.
why are the two different?