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	$153.61	7.191%	$164.6561	$164.66	$164.65	$164.70
Purchase #2	$49.40	6.438%	$52.5804	$52.58	$52.60	$52.60
Purchase #3	$80.85	6.189%	$85.8538	$85.85	$85.85	$85.90
Purchase #4	$53.35	4.701%	$55.858	$55.86	$55.85	$55.90
Purchase #5	$201.76	7.570%	$217.0332	$217.03	$217.05	$217.00
Purchase #6	$8.53	10.745%	$9.4465	$9.45	$9.45	$9.40
Purchase #7	$155.91	10.834%	$172.8013	$172.80	$172.80	$172.80
7 purchase totals =	$703.41		$758.2293	$758.23	$758.25	$758.30