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	$211.69	10.485%	$233.8857	$233.89	$233.90	$233.90
Purchase #2	$145.58	6.302%	$154.7545	$154.75	$154.75	$154.80
Purchase #3	$32.90	13.869%	$37.4629	$37.46	$37.45	$37.50
Purchase #4	$126.39	3.562%	$130.892	$130.89	$130.90	$130.90
Purchase #5	$157.52	5.108%	$165.5661	$165.57	$165.55	$165.60
Purchase #6	$144.29	10.487%	$159.4217	$159.42	$159.40	$159.40
Purchase #7	$134.49	7.378%	$144.4127	$144.41	$144.40	$144.40
7 purchase totals =	$952.86		$1,026.3956	$1,026.39	$1,026.35	$1,026.50