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	$184.55	12.625%	$207.8494	$207.85	$207.85	$207.80
Purchase #2	$191.72	13.789%	$218.1563	$218.16	$218.15	$218.20
Purchase #3	$12.98	8.837%	$14.127	$14.13	$14.15	$14.10
Purchase #4	$224.67	13.613%	$255.2543	$255.25	$255.25	$255.30
Purchase #5	$69.81	8.212%	$75.5428	$75.54	$75.55	$75.50
Purchase #6	$40.43	11.559%	$45.1033	$45.10	$45.10	$45.10
Purchase #7	$190.33	5.240%	$200.3033	$200.30	$200.30	$200.30
7 purchase totals =	$914.49		$1,016.3364	$1,016.33	$1,016.35	$1,016.30