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	$188.60	9.146%	$205.8494	$205.85	$205.85	$205.80
Purchase #2	$45.32	3.537%	$46.923	$46.92	$46.90	$46.90
Purchase #3	$19.64	9.255%	$21.4577	$21.46	$21.45	$21.50
Purchase #4	$185.55	8.296%	$200.9432	$200.94	$200.95	$200.90
Purchase #5	$191.56	7.677%	$206.2661	$206.27	$206.25	$206.30
Purchase #6	$93.82	12.591%	$105.6329	$105.63	$105.65	$105.60
Purchase #7	$234.36	4.306%	$244.4515	$244.45	$244.45	$244.50
7 purchase totals =	$958.85		$1,031.5238	$1,031.52	$1,031.50	$1,031.50