Pro Sites 3.5.0.4 Is not displaying checkout when upgrading from trial after expiration

Client is managing 3 sites, 1 is an Active paid pro site, 2 were queued to become active today. The 2 'to-be-active' sites have already had expired trials with "Pay to Blog" enabled.

Now; I logged into the Client Account to Upgrade the 2 'to-be-active' sites via checkout (Upgrade) with the clients supplied Credit Card; BUT, when I select the site to upgrade from the Account page, the checkout page does not display anything.

Screenshot: https://drive.google.com/file/d/0B_ouvJaDkX5SNUFseDBaakxSc0U/view?usp=sharing

-- I noticed the new Check out no longer uses wp-signup.php, could this be the issue?