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	$58.83	4.581%	$61.525	$61.53	$61.55	$61.50
Purchase #2	$157.36	11.467%	$175.4045	$175.40	$175.40	$175.40
Purchase #3	$124.78	7.382%	$133.9913	$133.99	$134.00	$134.00
Purchase #4	$133.30	13.319%	$151.0542	$151.05	$151.05	$151.10
Purchase #5	$243.33	8.532%	$264.0909	$264.09	$264.10	$264.10
Purchase #6	$70.33	3.242%	$72.6101	$72.61	$72.60	$72.60
Purchase #7	$192.50	4.280%	$200.739	$200.74	$200.75	$200.70
7 purchase totals =	$980.43		$1,059.4150	$1,059.41	$1,059.45	$1,059.40