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	$216.61	7.747%	$233.3908	$233.39	$233.40	$233.40
Purchase #2	$146.94	10.731%	$162.7081	$162.71	$162.70	$162.70
Purchase #3	$243.32	4.345%	$253.8923	$253.89	$253.90	$253.90
Purchase #4	$117.84	7.863%	$127.1058	$127.11	$127.10	$127.10
Purchase #5	$215.46	6.500%	$229.4649	$229.46	$229.45	$229.50
Purchase #6	$194.32	6.662%	$207.2656	$207.27	$207.25	$207.30
Purchase #7	$237.64	7.136%	$254.598	$254.60	$254.60	$254.60
7 purchase totals =	$1,372.13		$1,468.4255	$1,468.43	$1,468.40	$1,468.50