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	$95.30	7.297%	$102.254	$102.25	$102.25	$102.30
Purchase #2	$79.79	7.320%	$85.6306	$85.63	$85.65	$85.60
Purchase #3	$101.35	9.634%	$111.1141	$111.11	$111.10	$111.10
Purchase #4	$15.46	7.229%	$16.5776	$16.58	$16.60	$16.60
Purchase #5	$132.66	9.720%	$145.5546	$145.55	$145.55	$145.60
Purchase #6	$164.56	4.554%	$172.0541	$172.05	$172.05	$172.10
Purchase #7	$115.34	3.106%	$118.9225	$118.92	$118.90	$118.90
7 purchase totals =	$704.46		$752.1075	$752.09	$752.10	$752.20