Yep, low pressure relief valves often weep a little. You can get units that will seal better at low psi, but the finer the tolerance the more you will pay.

"Forget pounds and ounces, I'm figuring displacement!"

If we accept that: MBG(+)FGSF(=)HBG(F1)
And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1)
Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT?
PB answer: It depends.