> actually, you *must* dither at every truncation step - if you don't, you
This is a correct recommendation.
> some mastering people (bob katz among them) even go as far as demanding
Strictly speaking, this does not save you (and by you, I mean Bob
Katz). Further operations after dithering can 'break' the dither and
reintroduce distortion. Then you have the worst of both worlds; the
distortion _and_ the added noise.
Working at 24 bit / 32 float, this is academic and won't hurt you in
any audible way. It's too far below the audible floor to care about.