I was wondering this also. I sure hope they send out some more interview invites. I just got a status letter last Sat so hopefully there's more going out soon.
besides tomorrow they have 3 other interview in april and those are the last ones...i don't know if they have sent out all the letters yet...but they're getting very close
that means there's a chance if they havn't mailed all the letters out. there's a smaller chance if they have sent all the invitation letters out. because some of those invitations are gonna get turned down and open up another spot for an interview!