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	$116.96	9.104%	$127.608	$127.61	$127.60	$127.60
Purchase #2	$49.42	6.558%	$52.661	$52.66	$52.65	$52.70
Purchase #3	$244.95	13.809%	$278.7751	$278.78	$278.80	$278.80
Purchase #4	$136.71	11.650%	$152.6367	$152.64	$152.65	$152.60
Purchase #5	$236.78	3.369%	$244.7571	$244.76	$244.75	$244.80
Purchase #6	$120.45	4.739%	$126.1581	$126.16	$126.15	$126.20
Purchase #7	$217.43	7.478%	$233.6894	$233.69	$233.70	$233.70
7 purchase totals =	$1,122.70		$1,216.2854	$1,216.30	$1,216.30	$1,216.40