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	$219.44	10.168%	$241.7527	$241.75	$241.75	$241.80
Purchase #2	$224.53	13.756%	$255.4163	$255.42	$255.40	$255.40
Purchase #3	$52.34	13.325%	$59.3143	$59.31	$59.30	$59.30
Purchase #4	$65.26	10.624%	$72.1932	$72.19	$72.20	$72.20
Purchase #5	$128.61	12.551%	$144.7518	$144.75	$144.75	$144.80
Purchase #6	$233.61	11.415%	$260.2766	$260.28	$260.30	$260.30
Purchase #7	$123.71	13.336%	$140.208	$140.21	$140.20	$140.20
7 purchase totals =	$1,047.50		$1,173.9129	$1,173.91	$1,173.90	$1,174.00