Having issues with refrigerant readings…

Having issues with refrigerant readings… Installed a Guardian RC318 (1.5 ton condenser, R454B) with a new Guardian 40,000BTU furnace and new evaporator coil. Evap came with factory installed TXV (made sure TXV was positioned like the manual says). Also new lineset about 30’ long with new filter drier. Brazed all joints while flowing nitrogen. Vacuumed system to 109 microns and it passed the decay test. Existing ductwork is for a downflow system and the evaporator sits right on top of the concrete (horrible design, I know). Set cooling fan speed and got about 540 CFM at about .52” tesp. Started everything up and suction pressure was 125psi with 16 superheat. Head pressure was 250psi with 1 degree subcooling. I thought it needed charged, but after weighing in refrigerant for about an hour, the suction pressure went up a little and the superheat dropped slightly, but the head pressure and subcooling never changed. Suction temp was about 63 and liquid temp was about 89. Am I missing something? The system is cooling and the thermostat even satisfied before we left to about 74 in the house (outside temperature about 80).