As it pertains to this AF thread, the ability to hold any kind of pitch to within a degree or 2 at FL350 is nullfied by the presence of severe or extreme turbulence, the definition of which is the aircraft is at least sometimes "impossible to control", especially in a sluggish, wallowing aircraft. That means your pitch may be at least partially controlled not by you, but by outside forces you're merely fighting to counteract.
Throw in being knocked around on the roll axis with the corresponding sudden rises in wing loading (which will further serve to degrade speed and raise the low-speed buffet margin) threatening to stall one or both wings because you're high, and the only answer arises....pitch for a descent if possible to help maintain and increase aerodynamic control, and keep it right side up.
And if you're caught in a CB-produced severe updraft that lets go while you're still in a nose-up, level flight attitude based on FL350 numbers, at FL370 that same attitude puts you in a world of hurt. What works as an answer for the single problem of erroneous airspeed readings at 10000' or FL350 in smooth air isn't necassarily the best answer or what should be applied to what the AF likely found itself in.
spot on
