Quantity Discount : 28.75% to 36.25% off 5+ @ 28.75% : 71.86 + 12.93 (18%) = 84.79 10+ @ 32.50% : 68.08 + 12.25 (18%) = 80.33 15+ @ 36.25% : 64.29 + 11.57 (18%) = 75.86