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	$85.44	11.656%	$95.3989	$95.40	$95.40	$95.40
Purchase #2	$12.26	4.858%	$12.8556	$12.86	$12.85	$12.90
Purchase #3	$235.43	12.491%	$264.8376	$264.84	$264.85	$264.80
Purchase #4	$142.87	7.797%	$154.0096	$154.01	$154.00	$154.00
Purchase #5	$217.89	3.538%	$225.5989	$225.60	$225.60	$225.60
Purchase #6	$59.83	10.523%	$66.1259	$66.13	$66.15	$66.10
Purchase #7	$183.34	12.654%	$206.5398	$206.54	$206.55	$206.50
7 purchase totals =	$937.06		$1,025.3663	$1,025.38	$1,025.40	$1,025.30