If more than seven days after the date of an injury or at any time in case of death, the employer and the injured employee or his dependents reach an agreement in regard to compensation under this title, a memorandum of the agreement in the form prescribed by the commission, accompanied by a full and complete medical report shall be filed with the commission within fifteen days after agreement has been reached by the parties for approval of the commission; otherwise, such agreement shall be voidable by the employee or his dependents. All such agreements shall be subject to adjustment and correction as to the compensable rate if subsequent to filing with the commission it is determined that such rate does not reflect the correct average weekly wage of the claimant. If approved by the commission, the memorandum shall for all purposes be enforceable by a court’s decree as specified in this title.