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	$88.65	7.327%	$95.1454	$95.15	$95.15	$95.10
Purchase #2	$41.40	4.579%	$43.2957	$43.30	$43.30	$43.30
Purchase #3	$125.81	13.619%	$142.9441	$142.94	$142.95	$142.90
Purchase #4	$206.32	10.321%	$227.6143	$227.61	$227.60	$227.60
Purchase #5	$31.71	6.389%	$33.736	$33.74	$33.75	$33.70
Purchase #6	$241.37	12.807%	$272.2823	$272.28	$272.30	$272.30
Purchase #7	$207.47	8.735%	$225.5925	$225.59	$225.60	$225.60
7 purchase totals =	$942.73		$1,040.6103	$1,040.61	$1,040.65	$1,040.50