State laws differ, however typically the violation code for not wearing a seat belt and not wearing a seat belt properly is the same and thus the fine and penalties would be the same.

Not wearing a seat belt properly, unless you have a medical reason and thus a medical note to show why you cannot use the seat belt as it is intended, is basically the same as not wearing a seat belt to a law enforcement officer since without it being used correctly it would not be able to do its job or function if you were in an accident and needed it to.

For example, the California Vehicle Code (VC) states in Section 27315(d)(1) a person shall not operate a motor vehicle on a highway unless that person and all passengers 16 years of age or over are properly restrained by a safety belt.

Subsection (a) of this portion of the CA VC notes that the Legislature finds that a mandatory seatbelt law will contribute to reducing highway deaths and injuries by encouraging greater usage of existing manual seatbelts. So basically the reason for the seat belt law is to save lives and it is harder for this to happen if the driver and passengers in a vehicle do not properly wear their seat belt.

You can check with your state's Department of Motor Vehicles (DMV) to see if they can give you more information on your state laws and perhaps where in your state law you could read about the seat belt requirements.

If you were cited for not wearing your seat belt properly than you could also contact the court for information on your penalties and ask the clerk of the court if these are the same penalties one would receive for not wearing a seat belt at all.