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	$83.93	13.824%	$95.5325	$95.53	$95.55	$95.50
Purchase #2	$142.78	5.129%	$150.1032	$150.10	$150.10	$150.10
Purchase #3	$14.88	9.214%	$16.251	$16.25	$16.25	$16.30
Purchase #4	$90.57	10.634%	$100.2012	$100.20	$100.20	$100.20
Purchase #5	$110.81	5.108%	$116.4702	$116.47	$116.45	$116.50
Purchase #6	$80.66	12.184%	$90.4876	$90.49	$90.50	$90.50
Purchase #7	$182.84	8.237%	$197.9005	$197.90	$197.90	$197.90
7 purchase totals =	$706.47		$766.9462	$766.94	$766.95	$767.00