Tint legality is different everywhere. It keeps going up here. Local small pd's don't really mess with it, but state boys will get you every time.
If you do try the receipt from when it was tinted, it probably won't work. I tried that before.
Also, as tint ages, it turns purplish and causes it to read even darker on the meter, even though it looks lighter.
My husband is a police officer, and I understand their reasoning behind tint laws. If they can't see you in the car, then they don't know if your scratching your butt or pulling a gun.
I got pulled over for my tint (5 on the back, 20 on the sides) for the first time in three years about a month ago. It was a state trooper. Luckily he knew my husband and advised me since I'm fair complected I should get a prescription from my doctor, which I have been meaning to do. You could also try an eye doctor.