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	$13.59	8.505%	$14.7458	$14.75	$14.75	$14.70
Purchase #2	$84.64	11.178%	$94.1011	$94.10	$94.10	$94.10
Purchase #3	$210.56	8.636%	$228.744	$228.74	$228.75	$228.70
Purchase #4	$137.32	8.383%	$148.8315	$148.83	$148.85	$148.80
Purchase #5	$196.47	13.293%	$222.5868	$222.59	$222.60	$222.60
Purchase #6	$138.64	8.628%	$150.6019	$150.60	$150.60	$150.60
Purchase #7	$217.29	9.471%	$237.8695	$237.87	$237.85	$237.90
7 purchase totals =	$998.51		$1,097.4806	$1,097.48	$1,097.50	$1,097.40