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	$92.34	3.810%	$95.8582	$95.86	$95.85	$95.90
Purchase #2	$50.97	5.573%	$53.8106	$53.81	$53.80	$53.80
Purchase #3	$11.47	11.557%	$12.7956	$12.80	$12.80	$12.80
Purchase #4	$111.45	5.613%	$117.7057	$117.71	$117.70	$117.70
Purchase #5	$92.98	5.732%	$98.3096	$98.31	$98.30	$98.30
Purchase #6	$211.55	10.479%	$233.7183	$233.72	$233.70	$233.70
Purchase #7	$72.76	13.844%	$82.8329	$82.83	$82.85	$82.80
7 purchase totals =	$643.52		$695.0309	$695.04	$695.00	$695.00