I have recently installed an airdog fp100. The new gauge is reading 12-15 lbs. Is this ok or should I try changing the spring to get a little more press? I read all kinds of threads stating that people are getting 15/18/even 20 lbs. Is what I am getting normal for this setup? Honestly I expected more from what I have been reading. Truck is basically a stock 99', I left the stock setup in the tank and there are no other fuel system mods.