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	$231.49	13.157%	$261.9471	$261.95	$261.95	$261.90
Purchase #2	$237.96	7.571%	$255.976	$255.98	$256.00	$256.00
Purchase #3	$186.77	6.565%	$199.0315	$199.03	$199.05	$199.00
Purchase #4	$112.80	12.844%	$127.288	$127.29	$127.30	$127.30
Purchase #5	$68.46	4.592%	$71.6037	$71.60	$71.60	$71.60
Purchase #6	$109.96	9.267%	$120.15	$120.15	$120.15	$120.20
Purchase #7	$113.32	11.727%	$126.609	$126.61	$126.60	$126.60
7 purchase totals =	$1,060.76		$1,162.6053	$1,162.61	$1,162.65	$1,162.60