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	$206.26	9.457%	$225.766	$225.77	$225.75	$225.80
Purchase #2	$68.82	3.304%	$71.0938	$71.09	$71.10	$71.10
Purchase #3	$216.74	6.594%	$231.0318	$231.03	$231.05	$231.00
Purchase #4	$93.34	5.598%	$98.5652	$98.57	$98.55	$98.60
Purchase #5	$124.32	6.162%	$131.9806	$131.98	$132.00	$132.00
Purchase #6	$182.53	7.779%	$196.729	$196.73	$196.75	$196.70
Purchase #7	$141.42	10.192%	$155.8335	$155.83	$155.85	$155.80
7 purchase totals =	$1,033.43		$1,110.9999	$1,111.00	$1,111.05	$1,111.00