Its working fine. Basically, the more vacuum the motor is making, the less load it is under and the less fuel pressure it needs. If it were an N/A car, no vacuum in the motor (represented by pulling the vacuum line off the FPR) represents max load and thus, max fuel pressure. Now on a turbo car, once you go past "0 vacuum" you make positive pressure, causing fuel pressure to rise above that 39psi to compensate for boost.

You're going tonight right?