If back child support is paid and paid by the order date. What is the statue of limitations if any on interest ? Can the courts legaly come back years later and charge interest.If they didn't put it in the original orders?

According to Texas Family Code (157.261), the State of Texas allows for interest to be charged on missed support payments. Interest accrues on the delinquent child support at the rate of 6% simple interest per year from the date support is delinquent. Payment considered delinquent if not received before the 31st day after payment due date.

Texas also allows interest to be charged on retroactive support. Interest accrues from the date the court order is rendered at the rate of 6% simple interest per year.

It sounds like you may want to petition the courts on this one because courts have the authority to set aside a judgement of inclusion of interest or if your ex can agree on it. If you have been paying as court ordered then they may look in your favor.. either way you might need a lawyer to help you straighten it out.