This is a totally "unscientific" opinion (read, based on my memory), but I agree that they used to be "better", if based on accuracy alone.
There was a time, as you said --about 2-3 years ago, that they became unavailable for several months, nationwide from what I gathered on the internet shooting sites. Once they became available again, they never seemed to shoot as accurately in my 541 THB, which used to really love the things. It still shoots 'em pretty good, with the ocassional flyer. Man!, if I could isolate what makes that flyer, I'd be in "bulk-pak heaven"!!
And as far as muzzle vel., right again. Winchester lists the "Value Pak", supposed to be the same round -- diff. packaging, as 1150 fps. They are definitely more quiet out of my longer barreled bolts than the other bulk pack hi-vels.
All things considered, they are still my favorite bulkpak ammo, if for nothing else than the reduced report, and the fact that they reliably cycle in all my autos --including the Colt .22LR conversion in the AR....... I'm down to 3-4000 rounds, better get to Kmart and stock up!!!!