Clearly you are talking, with respect, pish.
Safety, it is about safety and ive just been checking out the City and guilds course work and none of what you suppose happens to coincide with reality. You were at no point ever taught to have the blade up at maximum, its something you've thought about in your head and have no proof to back it up.
Everything in the C&G is backed up by HSE regulation, and nowhere in regulation does it state blades should be set to maximum for all timber thicknesses.
As to efficiency, because thats what you're playing this as. Blade fully up dramatically increases the risk of kickback., and causes more saw marks to the cut surfaces. Its an aggressive way of doing it and because of that it is not recommended. You do it because you can rip the boards through faster. and in doing that there's more risk of complacency.
Im more about safety and doing things carefully and with thought. Safety factors are there for a very good reason.
Spindle moulders - just left to get on with it ?, what college was that. micky mouse central ?