That is just not normal unless you drive a ford, these do not run the same pressure hot as when cold
My old 86, M998. 6.2L. Clean and strong engine, 54K miles ? that's on the clock. No smoke unless at 6500 hundred feet. Lives at 2600 ft. no smoke down here. 70 degree start 45 PSI, When hot 25 to 35 running down the road. Hot idle 10 to 12. I have military and a mechanical guage, both track +/- OK. I don't worry about it (anymore) It is what it is and the book (TM) says good to go. Hot oil on a 2000 mile change... just pours out thin and black. Blacker than black. Drips for a half and hours. Filter, plug and refill. 15W-40W stenciled on the hood.
Runs like a top. 50 MPH all day long. Hold on for the HI SPEED test run at 60 for two minutes. No issues. Back down to 45 - 50.
Got to baby the beast. Slow and easy. Too damm expensive, CAMO