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	$175.63	11.612%	$196.0242	$196.02	$196.00	$196.00
Purchase #2	$11.42	6.788%	$12.1952	$12.20	$12.20	$12.20
Purchase #3	$187.41	8.348%	$203.055	$203.06	$203.05	$203.10
Purchase #4	$61.67	5.192%	$64.8719	$64.87	$64.85	$64.90
Purchase #5	$43.47	4.258%	$45.321	$45.32	$45.30	$45.30
Purchase #6	$63.28	13.710%	$71.9557	$71.96	$71.95	$72.00
Purchase #7	$126.45	3.516%	$130.896	$130.90	$130.90	$130.90
7 purchase totals =	$669.33		$724.3190	$724.33	$724.25	$724.40