The turnaround time for his "finished" to "published" is apparently 6 months. For other authors, it's actually a year.
3 months is supposedly possible, but probably unlikely when the publisher already has a release for him this year. Whereas if he were to finish by September 1st, we'd be looking at a March release next year. That'd probably be better for their accounting books.
Not that I know enough about the industry to know if that's accurate or not.
A lot of the publishers I used to work with liked Q1 releases. A lot of people get Amazon gift cards over the holidays (especially if they participate in office gift-giving), and there's not much you can get for $20 aside from a new book.
That said, this was back in the days when Kindles and Nooks and iPads and other tablets were all Shiny New Things, so maybe it made more business sense ten years ago. I remember Christmas morning was a particularly strong sales day for ebooks; people would unwrap their Kindle or whatever, and immediately look for something to read on it. Since it was still newish technology, most of them were trying ebooks for the first time, not porting over an existing library.
Anywho, I wouldn't discount the possibility of a Q4 release. Peace Talks is going to perform well for them pretty much whenever they release it, so it honestly depends on their performance over the summer (where you get the Nicholas Sparks-type releases usually, as they're strong beach books) and whether or not Jim can finish it in time. He's established himself well enough that he has some Protection from Editors (his name is almost as big as the title on the cover of Skin Game, and IS bigger on The Aeronaut's Windlass, which is the typical barometer for how much control the writer has over his story), so I don't think there will be many developmental rewrites.