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	$211.42	7.244%	$226.7353	$226.74	$226.75	$226.70
Purchase #2	$77.80	11.356%	$86.635	$86.64	$86.65	$86.60
Purchase #3	$114.81	7.387%	$123.291	$123.29	$123.30	$123.30
Purchase #4	$92.28	3.493%	$95.5033	$95.50	$95.50	$95.50
Purchase #5	$222.28	6.600%	$236.9505	$236.95	$236.95	$237.00
Purchase #6	$154.27	11.831%	$172.5217	$172.52	$172.50	$172.50
Purchase #7	$64.55	12.860%	$72.8511	$72.85	$72.85	$72.90
7 purchase totals =	$937.41		$1,014.4879	$1,014.49	$1,014.50	$1,014.50