Actually, it doesn't look like anything to do with DOJ settlement.
This program is completely voluntary for publisher - they have to sign up for it explicitly, Amazon can't just force their hand.
Also, it's the publisher who sets the price (from the limited set of 2.99, $1.99, $0.99, or free).
Source: http://phx.corporate-ir.net/phoenix.zhtml?c=176060&p=irol-ne...
Notice that the big US publishers are not yet mentioned as participating.