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	$175.29	11.698%	$195.7954	$195.80	$195.80	$195.80
Purchase #2	$175.93	5.172%	$185.0291	$185.03	$185.05	$185.00
Purchase #3	$76.76	13.698%	$87.2746	$87.27	$87.25	$87.30
Purchase #4	$125.53	11.406%	$139.848	$139.85	$139.85	$139.80
Purchase #5	$91.72	9.344%	$100.2903	$100.29	$100.30	$100.30
Purchase #6	$151.96	12.201%	$170.5006	$170.50	$170.50	$170.50
Purchase #7	$182.30	7.643%	$196.2332	$196.23	$196.25	$196.20
7 purchase totals =	$979.49		$1,074.9712	$1,074.97	$1,075.00	$1,074.90