It is possible that Tor/McMillan may have negotiated with Amazon to control some of their ebook prices. But Amazon controls most of their physical and ebook prices. The "Agency" model dictated that the publisher controlled the prices not Amazon, which is why they brought pressure on the DOJ.
The settlement was most definitely in Amazon's favor, freeing them to undercut prices to grab market share and drive out the competition (which was Apple's primary defense, that a judgement against Apple would allow Amazon to once again obtain it's defacto monopoly). Prior to the "Agency" model Amazon had a 90%+ market share of the ebook business. During the "Agency" model the share fell to 60%ish, hence the pressure by Amazon. Now it has not been a return to glory for them but it has resulted in a reasonable uptick in their share.
The DOJ asked book retailers to facilitate the distribution of the settlement through their customer base. As the manager of a B&N we were fully briefed on the case and it's implications.
However back to the main point, even assuming that Tor/McMillan has negotiated control the ebook price, Amazon controls the trade cloth price. That means Amazon made the conscious choice to bring the trade cloth price down to a few cents more than the ebook as a loss leader and that Tor/McMillan did not set out to muck with the prices.
And on a final note, checking invoices for previous Safehold books it looks like cost of goods on them is a smidge below $18 so you're getting a pretty good deal on the trade cloth at 15.70.
