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	$209.86	6.673%	$223.864	$223.86	$223.85	$223.90
Purchase #2	$58.99	10.773%	$65.345	$65.35	$65.35	$65.30
Purchase #3	$11.74	3.253%	$12.1219	$12.12	$12.10	$12.10
Purchase #4	$57.36	3.637%	$59.4462	$59.45	$59.45	$59.40
Purchase #5	$154.78	9.800%	$169.9484	$169.95	$169.95	$169.90
Purchase #6	$248.84	11.115%	$276.4986	$276.50	$276.50	$276.50
Purchase #7	$193.47	11.269%	$215.2721	$215.27	$215.25	$215.30
7 purchase totals =	$935.04		$1,022.4962	$1,022.50	$1,022.45	$1,022.40