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	$162.82	8.663%	$176.9251	$176.93	$176.95	$176.90
Purchase #2	$7.30	6.602%	$7.7819	$7.78	$7.80	$7.80
Purchase #3	$80.57	3.736%	$83.5801	$83.58	$83.60	$83.60
Purchase #4	$191.73	8.277%	$207.5995	$207.60	$207.60	$207.60
Purchase #5	$37.77	7.659%	$40.6628	$40.66	$40.65	$40.70
Purchase #6	$231.72	11.640%	$258.6922	$258.69	$258.70	$258.70
Purchase #7	$246.51	4.198%	$256.8585	$256.86	$256.85	$256.90
7 purchase totals =	$958.42		$1,032.1001	$1,032.10	$1,032.15	$1,032.20