Federal vehicle safety laws - which states adopt their own, but use the same guidelines, mandates that windows on passenger cars have 70% light transmittance (LT) on all windows, including the rear. This means that 70% of light must pass through the glass when measured with a meter. This does not mean that you can have 70% tint. (that would leave you with only 30% LT). Trucks and SUVs can have the rear windows and windows behind the driver and pass. door at any level.
Some laws are worded that if the window "prevents clear view of the interior of the vehicle" (or similar wording) they are in violation. This would not require a measurement of the glass, BUT would be open to argument in court as it is based on an opinion of the officer, and not a scientific measurment.
An officer may issue a seperate citation for each violation found on a vehicle. If 2 brakes are defective on a tractor trailer, 2 tickets. Same applies for passenger cars.
IMO, you must have angered this officer somehow, as normally you would be given 1 ticket for the tint. Were you polite? Courtesy will go a long way at a stop to prevent a ticket.
Personally, I would have measured the LT with a meter on the windows prior to issuing a ticket.
Good luck, whatever you decide.
Self - Police Officer / Motor Carrier Enforcement (14 years)