Quantity Discount : 28.75% to 36.23% off 5+ @ 28.75% : 36.23 + 6.52 (18%) = 42.75 10+ @ 32.48% : 34.33 + 6.18 (18%) = 40.51 15+ @ 36.23% : 32.42 + 5.84 (18%) = 38.26