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	$211.68	4.615%	$221.449	$221.45	$221.45	$221.40
Purchase #2	$95.48	10.176%	$105.196	$105.20	$105.20	$105.20
Purchase #3	$180.38	8.832%	$196.3112	$196.31	$196.30	$196.30
Purchase #4	$246.47	12.129%	$276.3643	$276.36	$276.35	$276.40
Purchase #5	$166.92	3.605%	$172.9375	$172.94	$172.95	$172.90
Purchase #6	$221.97	7.113%	$237.7587	$237.76	$237.75	$237.80
Purchase #7	$128.71	6.338%	$136.8676	$136.87	$136.85	$136.90
7 purchase totals =	$1,251.61		$1,346.8843	$1,346.89	$1,346.85	$1,346.90