fuel pressure drop

Is this a dampened gauge (fluid filled) and where is it installed? If it is in the engine compartment, your pressure is still 6 psi the temperature will cause the gauge to read low. I have a fluid filled gauge with a compensating valve, it will read low after warmed up, I open the compensating valve and it comes back up to my set pressure. I believe even the non fluid filled gauges are effected by heat under the hood.