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	$85.31	12.361%	$95.8552	$95.86	$95.85	$95.90
Purchase #2	$179.73	12.243%	$201.7343	$201.73	$201.75	$201.70
Purchase #3	$139.65	8.754%	$151.875	$151.88	$151.90	$151.90
Purchase #4	$248.39	5.669%	$262.4712	$262.47	$262.45	$262.50
Purchase #5	$39.27	9.152%	$42.864	$42.86	$42.85	$42.90
Purchase #6	$32.66	10.172%	$35.9822	$35.98	$36.00	$36.00
Purchase #7	$237.39	10.599%	$262.551	$262.55	$262.55	$262.60
7 purchase totals =	$962.40		$1,053.3329	$1,053.33	$1,053.35	$1,053.50