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	$219.33	5.287%	$230.926	$230.93	$230.95	$230.90
Purchase #2	$29.63	11.225%	$32.956	$32.96	$32.95	$33.00
Purchase #3	$70.26	3.568%	$72.7669	$72.77	$72.75	$72.80
Purchase #4	$149.79	7.269%	$160.6782	$160.68	$160.70	$160.70
Purchase #5	$123.54	12.545%	$139.0381	$139.04	$139.05	$139.00
Purchase #6	$25.78	11.550%	$28.7576	$28.76	$28.75	$28.80
Purchase #7	$86.72	4.447%	$90.5764	$90.58	$90.60	$90.60
7 purchase totals =	$705.05		$755.6992	$755.72	$755.75	$755.80