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	$161.82	3.788%	$167.9497	$167.95	$167.95	$167.90
Purchase #2	$200.49	9.449%	$219.4343	$219.43	$219.45	$219.40
Purchase #3	$143.27	10.573%	$158.4179	$158.42	$158.40	$158.40
Purchase #4	$239.78	4.200%	$249.8508	$249.85	$249.85	$249.90
Purchase #5	$161.61	3.141%	$166.6862	$166.69	$166.70	$166.70
Purchase #6	$49.74	8.382%	$53.9092	$53.91	$53.90	$53.90
Purchase #7	$43.70	8.595%	$47.456	$47.46	$47.45	$47.50
7 purchase totals =	$1,000.41		$1,063.7041	$1,063.71	$1,063.70	$1,063.70