I stumbled on this today, as I have a PH Zurich 3 night stay followed by a Cat7 cert night. Concierge would not confirm my suite upgrade request for the 3 night reservation. I guess this is standard knowledge but seems extremely punitive, since the T&C's say "...Suite Upgrade Award must be redeemed in connection with a reservation at a Hyatt hotel with a checkout date before the expiration date." . I can no longer use the cert at PH Zurich due to the recent category inflation, so I am stuck I guess.