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	$175.52	11.669%	$196.0014	$196.00	$196.00	$196.00
Purchase #2	$111.81	4.759%	$117.131	$117.13	$117.15	$117.10
Purchase #3	$178.58	6.838%	$190.7913	$190.79	$190.80	$190.80
Purchase #4	$160.71	3.473%	$166.2915	$166.29	$166.30	$166.30
Purchase #5	$126.28	11.496%	$140.7971	$140.80	$140.80	$140.80
Purchase #6	$125.67	10.739%	$139.1657	$139.17	$139.15	$139.20
Purchase #7	$102.72	10.248%	$113.2467	$113.25	$113.25	$113.20
7 purchase totals =	$981.29		$1,063.4247	$1,063.43	$1,063.45	$1,063.40