how inportant was/is a switching supply, and was incorporating it really as simple as copying a well-known design?
also, i think that in this case Job's has to characterized as ignorant or a liar.
he almost had no idea how power supplies work and this "invention" gave him the ability to credit someone other than woz for the Apple II success. which is how i read this qoute, as jobs usually didn't publicly praise people without a motive.
or.
he did realize how this work and lied to rewrite the books on what company made this contribution. i think it was a bit of both, but the ignorance allows one to attribute some of the mischarachterizations to lack of info rather than simple disingenuousness.