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	$163.71	10.874%	$181.5118	$181.51	$181.50	$181.50
Purchase #2	$205.92	13.321%	$233.3506	$233.35	$233.35	$233.40
Purchase #3	$49.70	11.571%	$55.4508	$55.45	$55.45	$55.50
Purchase #4	$165.77	6.461%	$176.4804	$176.48	$176.50	$176.50
Purchase #5	$100.92	11.287%	$112.3108	$112.31	$112.30	$112.30
Purchase #6	$124.59	4.679%	$130.4196	$130.42	$130.40	$130.40
Purchase #7	$156.51	10.391%	$172.773	$172.77	$172.75	$172.80
7 purchase totals =	$967.12		$1,062.2970	$1,062.29	$1,062.25	$1,062.40