Is there any way of adjusting the readings to make them more accurate.
No adjustments are possible. Accuracy is not what these are about. Fill your tires with air and use a known good tire gauge then see what the reading is on your display. If that drops more than a few lbs at a time then you know that you have a problem. Does that work better for ya Sparky?
Just seems weird that I can pump my tyres to 40 psi at the service station only to have them read 32psi when I pull away,