White Sands Forest Products (Defendant) purchased logging equipment from Clark Corporation (Plaintiff) under an installment contract that gave Plaintiff the right to repossess and resell the equipment if Defendant defaulted on the contract. Defendant did default and agreed to deliver the equipment to Plaintiff if Plaintiff would then discharge Defendant from further obligation. Plaintiff accepted delivery and resold the equipment, but the sale left a deficiency (there was still money owing by Defendant). Plaintiff then sued for the deficiency, and Defendant set up as a defense the accord and satisfaction. Is the defense good?