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	$174.88	12.341%	$196.4619	$196.46	$196.45	$196.50
Purchase #2	$72.38	4.719%	$75.7956	$75.80	$75.80	$75.80
Purchase #3	$172.59	7.770%	$186.0002	$186.00	$186.00	$186.00
Purchase #4	$143.36	13.237%	$162.3366	$162.34	$162.35	$162.30
Purchase #5	$59.47	13.830%	$67.6947	$67.69	$67.70	$67.70
Purchase #6	$48.82	6.680%	$52.0812	$52.08	$52.10	$52.10
Purchase #7	$206.55	7.377%	$221.7872	$221.79	$221.80	$221.80
7 purchase totals =	$878.05		$962.1574	$962.16	$962.20	$962.20