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	$190.54	3.155%	$196.5515	$196.55	$196.55	$196.60
Purchase #2	$239.37	6.831%	$255.7214	$255.72	$255.70	$255.70
Purchase #3	$169.88	3.252%	$175.4045	$175.40	$175.40	$175.40
Purchase #4	$195.34	6.787%	$208.5977	$208.60	$208.60	$208.60
Purchase #5	$49.52	11.137%	$55.035	$55.04	$55.05	$55.00
Purchase #6	$121.80	3.104%	$125.5807	$125.58	$125.60	$125.60
Purchase #7	$25.54	9.410%	$27.9433	$27.94	$27.95	$27.90
7 purchase totals =	$991.99		$1,044.8341	$1,044.83	$1,044.85	$1,044.80