Ranger, guessing that at this point they only addressed the extention of Nokia's time to file an Answering Brief. When they agreed to move THAT date out to April 28, it most likely also moved InterDigital's "basic 15 day time to respond"(?) date.
Maybe the door is still open for InterDigital to request an extention on that May 12 date after they see what Nokia files on April 28..??
Hoping that Nokia's extention is an accommodation for settlement negotiations, but one never knows until the facts are disclosed. Is this fun or what?