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	$92.64	3.513%	$95.8944	$95.89	$95.90	$95.90
Purchase #2	$136.76	12.217%	$153.468	$153.47	$153.45	$153.50
Purchase #3	$107.28	8.421%	$116.314	$116.31	$116.30	$116.30
Purchase #4	$38.72	3.176%	$39.9497	$39.95	$39.95	$39.90
Purchase #5	$13.32	11.610%	$14.8665	$14.87	$14.85	$14.90
Purchase #6	$196.84	4.150%	$205.0089	$205.01	$205.00	$205.00
Purchase #7	$115.30	9.812%	$126.6132	$126.61	$126.60	$126.60
7 purchase totals =	$700.86		$752.1147	$752.11	$752.05	$752.10