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	$84.85	11.644%	$94.7299	$94.73	$94.75	$94.70
Purchase #2	$156.58	5.485%	$165.1684	$165.17	$165.15	$165.20
Purchase #3	$222.92	11.391%	$248.3128	$248.31	$248.30	$248.30
Purchase #4	$217.45	5.453%	$229.3075	$229.31	$229.30	$229.30
Purchase #5	$172.46	7.582%	$185.5359	$185.54	$185.55	$185.50
Purchase #6	$215.74	6.837%	$230.4901	$230.49	$230.50	$230.50
Purchase #7	$183.27	9.414%	$200.523	$200.52	$200.50	$200.50
7 purchase totals =	$1,253.27		$1,354.0676	$1,354.07	$1,354.05	$1,354.00