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	$195.38	8.460%	$211.9091	$211.91	$211.90	$211.90
Purchase #2	$193.93	11.648%	$216.519	$216.52	$216.50	$216.50
Purchase #3	$42.86	6.239%	$45.534	$45.53	$45.55	$45.50
Purchase #4	$87.31	4.377%	$91.1316	$91.13	$91.15	$91.10
Purchase #5	$180.34	10.597%	$199.4506	$199.45	$199.45	$199.50
Purchase #6	$143.46	4.450%	$149.844	$149.84	$149.85	$149.80
Purchase #7	$94.55	8.644%	$102.7229	$102.72	$102.70	$102.70
7 purchase totals =	$937.83		$1,017.1112	$1,017.10	$1,017.10	$1,017.00