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	$191.53	4.754%	$200.6353	$200.64	$200.65	$200.60
Purchase #2	$198.42	9.418%	$217.1072	$217.11	$217.10	$217.10
Purchase #3	$153.31	11.780%	$171.3699	$171.37	$171.35	$171.40
Purchase #4	$152.38	11.297%	$169.5944	$169.59	$169.60	$169.60
Purchase #5	$73.25	9.560%	$80.2527	$80.25	$80.25	$80.30
Purchase #6	$143.50	9.333%	$156.8929	$156.89	$156.90	$156.90
Purchase #7	$59.39	7.392%	$63.7801	$63.78	$63.80	$63.80
7 purchase totals =	$971.78		$1,059.6325	$1,059.63	$1,059.65	$1,059.70