The USA Network has been throwing around some numbers of what they’d be willing to pay for an additional hour of Smackdown. While it’s still very early, USA is curious about whether a third hour of Smackdown would be viable.
WWE is very skeptical as the third hour of Raw has done a lot of harm to the level of viewership. However, it took time for the third hour to slowly erode the audience and based on when WWE's contract runs up, USA would have the benefit of the extra hour of ratings and if it eventually causes ratings to slide, all it does if give USA more leverage in the next negotiation. So there isn't nearly the same risk for USA as there is for WWE.
Sources have indicated that WWE prefers to table the issue until the next TV contract. Had USA gotten their way, Smackdown would have gone to three hours as soon as possible. Another factor though is while WWE’s biggest international television partners were fine with the switch to Tuesdays, they were not eager to pay more for an additional hour.