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	$213.32	5.626%	$225.3214	$225.32	$225.30	$225.30
Purchase #2	$11.55	7.842%	$12.4558	$12.46	$12.45	$12.50
Purchase #3	$152.70	5.743%	$161.4696	$161.47	$161.45	$161.50
Purchase #4	$184.74	3.318%	$190.8697	$190.87	$190.85	$190.90
Purchase #5	$217.80	11.414%	$242.6597	$242.66	$242.65	$242.70
Purchase #6	$76.87	5.642%	$81.207	$81.21	$81.20	$81.20
Purchase #7	$118.25	7.719%	$127.3777	$127.38	$127.40	$127.40
7 purchase totals =	$975.23		$1,041.3609	$1,041.37	$1,041.30	$1,041.50