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	$196.99	4.407%	$205.6713	$205.67	$205.65	$205.70
Purchase #2	$10.57	12.466%	$11.8877	$11.89	$11.90	$11.90
Purchase #3	$52.39	8.696%	$56.9458	$56.95	$56.95	$56.90
Purchase #4	$116.72	9.184%	$127.4396	$127.44	$127.45	$127.40
Purchase #5	$37.65	7.796%	$40.5852	$40.59	$40.60	$40.60
Purchase #6	$128.54	11.399%	$143.1923	$143.19	$143.20	$143.20
Purchase #7	$186.69	13.221%	$211.3723	$211.37	$211.35	$211.40
7 purchase totals =	$729.55		$797.0942	$797.10	$797.10	$797.10