It is conceivable that they told the J's,

"look we will reduce the settlement by X amount. We feel very strongly about the potential for appeal on the 584. We've also had positive feedback from the USPTO. That being the said, if we win on appeal, you will have saved several million each. If we lose, you didn't pay for it to begin with so it's water under the bridge."

Maybe Alliacense finally gave some headway on the issue figuring closure was more important. ARM is the primary focus of the 584 anyways. Between the Markman and perhaps some compromise by Alliacense on the 584, it finally brought everyone to terms. I know the 336 and 148 are the meat and potatoes but I'm sure they tried to keep the 584 in play as long as possible. After the Markman, Leckrone sure made it sound like there was room for interpretation on the 584. Perhaps they made a good will gesture and removed it from the equation making the pill easier to swallow for the J's. Who knows.