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	$114.27	3.492%	$118.2603	$118.26	$118.25	$118.30
Purchase #2	$51.54	11.376%	$57.4032	$57.40	$57.40	$57.40
Purchase #3	$185.72	11.431%	$206.9497	$206.95	$206.95	$206.90
Purchase #4	$247.37	3.684%	$256.4831	$256.48	$256.50	$256.50
Purchase #5	$54.51	12.611%	$61.3843	$61.38	$61.40	$61.40
Purchase #6	$69.84	3.581%	$72.341	$72.34	$72.35	$72.30
Purchase #7	$208.51	13.506%	$236.6714	$236.67	$236.65	$236.70
7 purchase totals =	$931.76		$1,009.4930	$1,009.48	$1,009.50	$1,009.50