Set,
They (the makers) claim it doesn't, I believe. My experience is that it seems to actually expand. We are talking about only the "real" Acouta-Stuff.
I doubt if settling is an issue (with that product), BUT stuffing a cabinet and having the drivers themselves change over time might lead one to believe it is the stuffing settling when in fact the drivers' suspension is finally loosening up resulting in a change of parameters different than the design called for.
But hey, I could be wrong.
Ed
Added....I am mainly talking about DIY with new drivers in cabinets "stuffed by ear" using an "educated guess"!