From a little experience and reading the American Standards testing procedures, there appears not to be any increase in adhesive quality, however the degree of
water resistance is markedly increased...
Being Americans, they do state & print on the
Titebond III bottle that it is Waterproof
...however what they really mean that it is very, very, very, very resistant to water unsticking the pieces of wood.
.
However they do not state nor even make the slightest suggestion that it is suitable for adhering wood to plastic body filler.....