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	$90.97	4.725%	$95.2683	$95.27	$95.25	$95.30
Purchase #2	$201.55	3.473%	$208.5498	$208.55	$208.55	$208.50
Purchase #3	$126.33	12.268%	$141.8282	$141.83	$141.85	$141.80
Purchase #4	$192.65	3.742%	$199.859	$199.86	$199.85	$199.90
Purchase #5	$5.80	7.792%	$6.2519	$6.25	$6.25	$6.30
Purchase #6	$201.26	6.538%	$214.4184	$214.42	$214.40	$214.40
Purchase #7	$143.51	4.688%	$150.2377	$150.24	$150.25	$150.20
7 purchase totals =	$962.07		$1,016.4133	$1,016.42	$1,016.40	$1,016.40