Let's do some math ..  Rounding examples of 7 random hypothetical purchases:
Case	Tag   Price	Sales   Tax %	Raw Total   Incl. Sales Tax	Rounded   to Penny	Rounded   to Nickel	Rounded   to Dime
Purchase #1	$85.32	11.384%	$95.0328	$95.03	$95.05	$95.00
Purchase #2	$140.56	8.258%	$152.1674	$152.17	$152.15	$152.20
Purchase #3	$141.34	11.647%	$157.8019	$157.80	$157.80	$157.80
Purchase #4	$151.52	11.109%	$168.3524	$168.35	$168.35	$168.40
Purchase #5	$97.46	9.103%	$106.3318	$106.33	$106.35	$106.30
Purchase #6	$171.78	7.353%	$184.411	$184.41	$184.40	$184.40
Purchase #7	$175.50	8.792%	$190.93	$190.93	$190.95	$190.90
7 purchase totals =	$963.48		$1,055.0273	$1,055.02	$1,055.05	$1,055.00