Court costs are added on after the fact. The amount that is stated on the ticket is the amount you have the option of paying in order to avoid the court date.
I think we have one of two Scenarios going on here.
A. Dickhead Nazi-Cop decides he want's to fuck with someone because he's had a rough day. Decides to give some poor mother hell over a failing to wear a seatbelt properly. Instead of putting the actual amount (likely $30) on the ticket he decides to really be a cocksucker and puts down $125, betting on the fact she'll just pay the fine and move on. (I've been involved in a couple of these circumstances where Officer Cocksucker - for no reason- is just a giant raging asshole right off the bat. Rare, but it does happen.)
B. (No Offense to your Wife) Decent cop pulls over a Mother in order to give her a lecture about not wearing her seat belt. She's in a rush, on the rag, and by all means has her seatbelt on so she gets an attitude. Cop remains calm, but this women just wont let it go. Finally Cop says "man fuck this chick" and throws the book at her.
Honestly I think it could go either way at this point, so many "WTF" things about this case. If you could post the ticket/narrow down the Issuing Officer/Agency it could really help narrow down what likely happened. I can't imagine CPD or OSHP pulling this kind of Crap, although Suburb Cops/Sheriff's?, Definitely.