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	$204.45	10.504%	$225.9254	$225.93	$225.95	$225.90
Purchase #2	$231.88	10.305%	$255.7752	$255.78	$255.80	$255.80
Purchase #3	$126.76	9.785%	$139.1635	$139.16	$139.15	$139.20
Purchase #4	$138.39	5.366%	$145.816	$145.82	$145.80	$145.80
Purchase #5	$124.33	10.414%	$137.2777	$137.28	$137.30	$137.30
Purchase #6	$50.74	5.577%	$53.5698	$53.57	$53.55	$53.60
Purchase #7	$78.84	10.838%	$87.3847	$87.38	$87.40	$87.40
7 purchase totals =	$955.39		$1,044.9123	$1,044.92	$1,044.95	$1,045.00