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	$182.25	4.333%	$190.1469	$190.15	$190.15	$190.10
Purchase #2	$181.79	10.290%	$200.4962	$200.50	$200.50	$200.50
Purchase #3	$216.85	12.642%	$244.2642	$244.26	$244.25	$244.30
Purchase #4	$16.91	8.142%	$18.2868	$18.29	$18.30	$18.30
Purchase #5	$122.76	3.230%	$126.7251	$126.73	$126.75	$126.70
Purchase #6	$131.42	7.355%	$141.0859	$141.09	$141.10	$141.10
Purchase #7	$130.30	12.438%	$146.5067	$146.51	$146.50	$146.50
7 purchase totals =	$982.28		$1,067.5118	$1,067.53	$1,067.55	$1,067.50