Quantity Discount : 28.75% to 36.25% off 5+ @ 28.75% : 475.81 + 85.65 (18%) = 561.46 10+ @ 32.50% : 450.77 + 81.14 (18%) = 531.91 15+ @ 36.25% : 425.72 + 76.63 (18%) = 502.35