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	$85.75	11.311%	$95.4492	$95.45	$95.45	$95.40
Purchase #2	$178.29	4.511%	$186.3327	$186.33	$186.35	$186.30
Purchase #3	$65.55	10.839%	$72.655	$72.66	$72.65	$72.70
Purchase #4	$12.69	8.680%	$13.7915	$13.79	$13.80	$13.80
Purchase #5	$39.53	7.650%	$42.554	$42.55	$42.55	$42.60
Purchase #6	$230.63	13.327%	$261.3661	$261.37	$261.35	$261.40
Purchase #7	$201.75	10.548%	$223.0306	$223.03	$223.05	$223.00
7 purchase totals =	$814.19		$895.1791	$895.18	$895.20	$895.20