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	$206.35	11.260%	$229.585	$229.59	$229.60	$229.60
Purchase #2	$57.31	4.873%	$60.1027	$60.10	$60.10	$60.10
Purchase #3	$168.61	13.608%	$191.5544	$191.55	$191.55	$191.60
Purchase #4	$53.47	11.748%	$59.7517	$59.75	$59.75	$59.80
Purchase #5	$105.70	12.448%	$118.8575	$118.86	$118.85	$118.90
Purchase #6	$178.96	12.169%	$200.7376	$200.74	$200.75	$200.70
Purchase #7	$138.36	11.424%	$154.1662	$154.17	$154.15	$154.20
7 purchase totals =	$908.76		$1,014.7551	$1,014.76	$1,014.75	$1,014.90