The interested parties may settle all matters of benefits, whether involving compensation, medical payments, or rehabilitation, and all questions arising under this article and Article 4 of this chapter between themselves, and every settlement shall be in an amount the same as the amounts or benefits stipulated in this article. No settlement for an amount less than the amounts or benefits stipulated in this article shall be valid for any purpose, unless a judge of the court where the claim for compensation under this chapter is entitled to be made, or upon the written consent of the parties, a judge of the court determines that it is for the best interest of the employee or the employee's dependent to accept a lesser sum and approves the settlement. The court shall not approve any settlement unless and until it has first made inquiry into the bona fides of a claimant's claim and the liability of the defendant; and if deemed advisable, the court may hold a hearing thereon. Settlements made may be vacated for fraud, undue influence, or coercion, upon application made to the judge approving the settlement at any time not later than six months after the date of settlement. Upon settlements being approved, judgment shall be entered thereon and duly entered on the records of the court in the same manner and have the same effect as other judgments or as an award if the settlement is not for a lump sum. All moneys voluntarily paid by the employer or insurance carrier to an injured employee in advance of agreement or award shall be treated as advance payments on account of the compensation. In order to encourage advance payments, it is expressly provided that the payments shall not be construed as an admission of liability but shall be without prejudice.