Yeah, I promised to get back to that later.
Turns out, I lied about explaining it later. Gary from View from the Wing reports:
They’ve eliminated their ‘off peak’ 60,000 mile business class award (55,000 miles for US Airways credit card holders) from North America including Hawaii to Europe. Now the only off-peak premium cabin awards are to South America and the Caribbean.
I won’t bother explaining this, since it is now going away!
The devaluations in US Airway’s award chart go further than this, and Gary explains it in that post. The important thing is, this doesn’t affect awards on partner carriers, what I prefer to use my US Airways miles on in international travel anyway.