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	$205.38	3.754%	$213.09	$213.09	$213.10	$213.10
Purchase #2	$31.88	12.475%	$35.857	$35.86	$35.85	$35.90
Purchase #3	$208.72	13.798%	$237.5192	$237.52	$237.50	$237.50
Purchase #4	$131.87	12.493%	$148.3445	$148.34	$148.35	$148.30
Purchase #5	$167.86	4.317%	$175.1065	$175.11	$175.10	$175.10
Purchase #6	$221.42	6.342%	$235.4625	$235.46	$235.45	$235.50
Purchase #7	$112.43	3.733%	$116.627	$116.63	$116.65	$116.60
7 purchase totals =	$1,079.56		$1,162.0067	$1,162.01	$1,162.00	$1,162.00