Miller,
I think the bulges look just like what you say they are. Obstructional bulges. Thanks for putting the differences between elastic and yield in a clear light.
Unfortunately, I don't see any further data coming to light out of this situation.
Further, I don't see how a sound tube, open at one end, can be considered safe at 8K and a ticking time bomb at 10K.
Unless it is obstructed.

Best,
Ted