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	$196.60	4.632%	$205.7065	$205.71	$205.70	$205.70
Purchase #2	$232.81	4.123%	$242.4088	$242.41	$242.40	$242.40
Purchase #3	$138.56	5.319%	$145.93	$145.93	$145.95	$145.90
Purchase #4	$87.72	4.577%	$91.7349	$91.73	$91.75	$91.70
Purchase #5	$120.83	10.349%	$133.3347	$133.33	$133.35	$133.30
Purchase #6	$103.85	4.792%	$108.8265	$108.83	$108.85	$108.80
Purchase #7	$126.69	11.214%	$140.897	$140.90	$140.90	$140.90
7 purchase totals =	$1,007.06		$1,068.8384	$1,068.84	$1,068.90	$1,068.70