Holley 12-887 fuel pressure regulator

Does anyone else run a Holley 12-887 fuel pressure 3 port regulator? It seems mine needs a little adjustment back to 6.5 PSI which is where I prefer to set my regulator from time to time. Holley states the fuel pressure should be set @ 5 to 7 PSI for my XP carb. I personally think temperature which effects Fuel density which contributes to variance of the setting. Im not positive about all my theories ....... but do feel it plays a big factor. Does anyone else have this issue? Please advise Texas Red