to Rainboe
Though your comment wasn't necessarily directed at me, I didn't make reference to a theoretical paper on my previous post but rather a direct quote from the 'Boeing Flight Crew Operations' manual and said 'Bulletin' is still (IE) 'In Effect' so as far as conventional wisdom suggests perhaps a buzz to Tech Pilot or Tech Dept of one's largest airline to ask for Boeing's latest bulletin updates is in order.
Furthermore, I don't think that ice crystals have the ability to distinguish between aircraft or engine types.
Blue skies,
MC