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	$71.53	6.188%	$75.9563	$75.96	$75.95	$76.00
Purchase #2	$230.67	7.368%	$247.6658	$247.67	$247.65	$247.70
Purchase #3	$87.46	13.131%	$98.9444	$98.94	$98.95	$98.90
Purchase #4	$84.42	6.519%	$89.9233	$89.92	$89.90	$89.90
Purchase #5	$147.83	6.395%	$157.2837	$157.28	$157.30	$157.30
Purchase #6	$161.48	4.222%	$168.2977	$168.30	$168.30	$168.30
Purchase #7	$173.30	7.229%	$185.8279	$185.83	$185.85	$185.80
7 purchase totals =	$956.69		$1,023.8991	$1,023.90	$1,023.90	$1,023.90