I had difficulty at first getting into E+ as the United computer was not showing availability to the reservationists when they put in my US status. I ended up having to ask for a supervisor to over-ride the system and "get in" manually.

I ended up getting a match status on UA, so now it is no longer a problem for me personally.

However, they were working on the issue and I hope this is being resolved in order for the UA computer seating system to open up for US frequent fliers.