Could this be something to do with the percentage change in the amount of money the away team gets now if tickets are sold. Not sure of the figure, but I understand if the away fans buy tickets from their own club then their club gets a bigger cut now tha last season. Leigh was one of the clubs who voted against it saying it will cost them a lot in lost revenue. Obviously the clubs with a big away following voted for it.
So if you buy an away ticket buy it from Saints as they get more money.