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	$174.74	12.145%	$195.9622	$195.96	$195.95	$196.00
Purchase #2	$108.82	7.197%	$116.6518	$116.65	$116.65	$116.70
Purchase #3	$116.82	11.724%	$130.516	$130.52	$130.50	$130.50
Purchase #4	$128.31	5.839%	$135.802	$135.80	$135.80	$135.80
Purchase #5	$194.91	12.451%	$219.1782	$219.18	$219.20	$219.20
Purchase #6	$105.72	11.656%	$118.0427	$118.04	$118.05	$118.00
Purchase #7	$94.39	6.226%	$100.2667	$100.27	$100.25	$100.30
7 purchase totals =	$923.71		$1,016.4196	$1,016.42	$1,016.40	$1,016.50