Mazda Millenia - 1998 - Tire Noise - Uneven tire wear

I purchased a set of 4 Continental CH 95's and currently have 8,500 miles on
the tires. The first 5,500 miles the tires were fine...no problems or
complaints. The tires started to make noise between 15 and 40 mph after
rotating them for the first time (front to rear, rear to front - same side).
The noise got progressively worse and when the tires had 8,500 miles on them
(3,500 miles after the first rotation) I went back to the tire dealer he
said the tires were noisey because the rear tires were cupping (scalloping)
and it was the fault of the alignment. I then had the alignment checked and
it was within Maxda's specs. I'm blaming the tires and the dealer is blaming
the car.

I found the following information on Mark Salem's website.
http://marksalem.com/auto-maintenance/mb08.htm

"Cupping or scalloping of the tread, rough uneven wear, tread looks like it
is corrugated, tire is very lumpy and bumpy - generally caused by the tire
itself. Look to see if the words "All Season" are on the sidewall of the
tire. If the tire is an all season and you have a front wheel drive car and
the rear tires look like someone took a hot knife and scooped out small
pieces of rubber and the shocks are not leaking oil and there is no other
symptoms of bad shocks, then the tire is probably at fault. This symptom is
one that sells more shocks when, in my opinion, 90% of all cupping or
scalloping is caused by the tire itself"

Anyone else out there have/had a similar problem with Continentals or any
other tire brand??

Thanks,
Marc