Every pressure gauge I have ever used, regardless of brand, bleeds off some air when connected to or released from the valve stem. Digital, traditional analog, stick, round gauge, makes no difference. Just inflate X pounds over desired pressure and go forward. (X = known pressure bleed off of gauge)
As an aside I ran all my tires at 120 when racing. Another fella suggested I lower the pressure by 20. That was twenty years ago and have maintained 100 psi across the board on the 25mm tires I run, and 90-100 on the 28mm tires. Comfort level is much better at the lower psi. Interestingly enough I have fewer flats as well. Only run conti tires. The GP is the best riding with grip out there.