We drove into JFK for our interview and had our GE almost immediately so I'm betting you'll be okay for both trips but don't forget to enter it into your airline profile so it's there when you do your early check-in.

And with regard to the mobile ap, I don't have it (for no good reason....) but my daughter also says it's quicker than using GE since you answer all the entry questions on your phone and scan it and you're done and you get to go to the head of the lines. <img src="http://www.traveltalkonline.com/forums/images/graemlins/handshake.gif" alt="" /> <img src="http://www.traveltalkonline.com/forums/images/graemlins/handshake.gif" alt="" />