PSI when measured at the gun is always done with the trigger pulled so air is flowing through it.
Each product will have a recommendation for gun setting as will the gun manufacturer for given material products.
Some things that might help are
1) what gun were you using?
2) what clear were you spraying?
Orange Peel can be the result of too low air pressure.
Thoughts and comments expressed by me are mine based on my own experience and research and shared here freely. I am not a professional nor make any claim to be as such