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	$169.60	7.681%	$182.627	$182.63	$182.65	$182.60
Purchase #2	$60.89	6.392%	$64.7821	$64.78	$64.80	$64.80
Purchase #3	$33.93	6.254%	$36.052	$36.05	$36.05	$36.10
Purchase #4	$177.79	7.133%	$190.4718	$190.47	$190.45	$190.50
Purchase #5	$21.60	12.424%	$24.2836	$24.28	$24.30	$24.30
Purchase #6	$180.73	13.198%	$204.5827	$204.58	$204.60	$204.60
Purchase #7	$55.46	6.562%	$59.0993	$59.10	$59.10	$59.10
7 purchase totals =	$700.00		$761.8985	$761.89	$761.95	$762.00