Given you are usually spot on with your info Spanners, I'm going to say that sounds pretty certain.
On the contrary, Spanners "info" about VS was incorrect about MAN-ATL being reduced to 5 per week (back on post 4617) and I'm led to believe that his timing is six months out on this likely development as well.
What I would also like VS to do is utilise the 2nd based A330 a bit more in the summer.
As I understand it, the aircraft at MAN is a spare from a gap in their heavy check cycle over the summer peak. The constraint may well be crew-related, in that it usually isn't worth employing extra crew for 52 weeks a year to fly for only six or seven weeks. Whether that changes for 2017 with the possibility to add extra SFO, BOS, BGI flights is anyone's guess, but either way, I'd be pretty sure the powers-that-be at VS are already well aware they have an aircraft sitting in MAN for four days a week in July and August.