Tires: Uneven tire wear pattern, smooth road surface, 2008 chevy malibu

Question
I noticed a sort of "fluttering" road noise when driving my 2008 Chevy Malibu Hybrid on any smooth road surface at speeds above about 40 mph. Suspecting a tire problem I had the tires checked at a tire store and they found cupping or scalloping on all 4 tires on the inside edges. I have just 14,000 miles on the new car and had the tires rotated once at about 6,500 miles. They suspected an alignment problem at the tire dealer so I went to the new car dealer and had the alignment checked and they said it was in spec.
What else could be causing the scalloping or is it possibly defective tires?

Answer
Curt,

My experience is that the vehicle manufacturer's alignment specs are too wide by half.  In other words, to prevent tire water issues, the alignment has to be within the inner half of the spec.

BTW, tire do not wear funny by themselves.  Funny wear is always caused by a vehicle alignment issue.  It's just that some tires are more sensitive than others.

But take the vehicle back to the dealer.  If I remember correctly, GM cars have a 3 year 36K warranty and it covers tires as well.  Be prepared to be asked to wait until the tires wear a bit more before they are replaced.