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	$44.42	5.482%	$46.8551	$46.86	$46.85	$46.90
Purchase #2	$114.78	7.641%	$123.5503	$123.55	$123.55	$123.60
Purchase #3	$246.71	4.315%	$257.3555	$257.36	$257.35	$257.40
Purchase #4	$216.65	8.861%	$235.8474	$235.85	$235.85	$235.80
Purchase #5	$178.95	9.787%	$196.4638	$196.46	$196.45	$196.50
Purchase #6	$131.72	9.515%	$144.2532	$144.25	$144.25	$144.30
Purchase #7	$152.52	11.189%	$169.5855	$169.59	$169.60	$169.60
7 purchase totals =	$1,085.75		$1,173.9108	$1,173.92	$1,173.90	$1,174.10