Granted on the fluid change. It was done recent enough that I'm still showing good red color on the dipstick. The previous owner was an extended family member, so I am comfortable with the service history.
I rechecked this afternoon after a short drive. Got an accurate, between the marks reading this time. I'm not sure what happened on the cold reading. Got the same +20mm after several readings when cold. Anyway, note to self to do checks with idling, warm engine.