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	$124.26	3.215%	$128.255	$128.26	$128.25	$128.30
Purchase #2	$8.95	11.631%	$9.991	$9.99	$10.00	$10.00
Purchase #3	$75.65	3.107%	$78.0004	$78.00	$78.00	$78.00
Purchase #4	$198.45	13.561%	$225.3618	$225.36	$225.35	$225.40
Purchase #5	$100.37	11.362%	$111.774	$111.77	$111.75	$111.80
Purchase #6	$200.84	10.689%	$222.3078	$222.31	$222.30	$222.30
Purchase #7	$227.30	5.806%	$240.497	$240.50	$240.50	$240.50
7 purchase totals =	$935.82		$1,016.1870	$1,016.19	$1,016.15	$1,016.30