Opencart - Less reward by coupon used

gistfile1.txt

DS15030247
Coupon value: $12.7
Total price(exclude shipping): $127
Sys reward: 89 + 16 = 105 (less )
Collect reward: $127 - $12.7 = 114.3

Products qty:
	10 + 1pcs
(RA)reward adjustment of coupon
	$12.7 / 11 = 1.15

Machine calc
a) 	10pcs * $10 - 1.15(RA) * 10
		= 100 - 11.5
		= 88.5
		= 89(round up)

b)	1pc * $27 - 1.15(RA)
		= 27 - 1.15
		= 25.85
		= 26(round up)