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	$196.95	10.151%	$216.9424	$216.94	$216.95	$216.90
Purchase #2	$10.46	8.410%	$11.3397	$11.34	$11.35	$11.30
Purchase #3	$177.42	7.286%	$190.3468	$190.35	$190.35	$190.30
Purchase #4	$201.93	4.387%	$210.7887	$210.79	$210.80	$210.80
Purchase #5	$212.48	3.864%	$220.6902	$220.69	$220.70	$220.70
Purchase #6	$144.32	8.289%	$156.2827	$156.28	$156.30	$156.30
Purchase #7	$89.71	10.459%	$99.0928	$99.09	$99.10	$99.10
7 purchase totals =	$1,033.27		$1,105.4833	$1,105.48	$1,105.55	$1,105.40