Here is copy of the latest installation manual page. Clearly they say the pressure is a checked and has to be with reference to the manifold pressure. It is there way of saying you have to measure the delta of the 2 and maintain your pressure relative to the manifold fluctuations that occur. (pressure differential)
A note, the fuel pressure control is a mechanical device, as such it has a number of small bits and whenever we see this design, (common automotive parts) there is always over and undershoot of pressures. The extent of these over and under readings normally will not affect your engine. The instrument supplier, if they are going to measure this , needs to be wary and not set his alarms too narrow.
Cleaver technicians have learned that the first signs of a contaminated filter is higher pressures. When a person says he cant turn on both fuel pumps or fuel pressure is too high this is the first thing to check. look for contaminated filters or problems with your fuel return to tank. I have seen rubber from the inside of fuel lines also contaminate the fuel pressure regulator, don't forget to check this if all else fails. Its not hard to take apart and clean.
Cheer
