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	$196.36	4.414%	$205.0273	$205.03	$205.05	$205.00
Purchase #2	$159.87	6.744%	$170.6516	$170.65	$170.65	$170.70
Purchase #3	$76.82	4.571%	$80.3314	$80.33	$80.35	$80.30
Purchase #4	$188.78	6.349%	$200.7656	$200.77	$200.75	$200.80
Purchase #5	$153.80	5.650%	$162.4897	$162.49	$162.50	$162.50
Purchase #6	$196.80	7.304%	$211.1743	$211.17	$211.15	$211.20
Purchase #7	$89.48	3.439%	$92.5572	$92.56	$92.55	$92.60
7 purchase totals =	$1,061.91		$1,122.9971	$1,123.00	$1,123.00	$1,123.10