If your regulator is working properly and is tapped into the manifold at the right place, you will see boost and fuel pressure increase in a 1:1 ratio.
If your base fuel pressure is at the stock setting (39psi), you will see 49psi at the rail under 10psi of boost. All this is doing is keeping the same pressure at the injector tip. If there is 10PSI of air pushing air INTO the injector, you also need 10PSI more pressure pushing fuel out to keep it equal so that the PCM can calculate the required fuel.
Wes