If the child turns 18 and you still have to support them, can the Custodial parent go back and have child support raised after the age of 18? My step-dauhter turns 18 Dec.10th and we have to pay until she graduates. (Aug. 10,2010) she is homeschooled. But we pay an extra $35 a week that is not auto tken from my husbands pay, can we swtop this payment, it is just an agreement between them not a court order. He wants to stop that payment and just pay the court ordered but he is afraid she will take him back to court and get CS raised. I don't think she can after the child turns 18. HELP!!

First its not a good idea to piggyback your question on someone else's. This can lead to confusion. You should start a new thread. So I've moved your question to its own thread.

Until the support order expires, either parent can go back for a modification if circumstances change. And that's the key circumstances have to change. If his income has not materially changed then its unlikely a court will order a change in the amount. If the side payment is not part of a legally binding agreement then he can probably stop it. She could take him to court, but I doubt if she will get a modification.