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	$175.34	11.799%	$196.0284	$196.03	$196.05	$196.00
Purchase #2	$171.90	4.136%	$179.0098	$179.01	$179.00	$179.00
Purchase #3	$66.92	7.553%	$71.9745	$71.97	$71.95	$72.00
Purchase #4	$73.71	6.162%	$78.252	$78.25	$78.25	$78.30
Purchase #5	$188.53	9.672%	$206.7646	$206.76	$206.75	$206.80
Purchase #6	$106.89	5.422%	$112.6856	$112.69	$112.70	$112.70
Purchase #7	$240.91	8.216%	$260.7032	$260.70	$260.70	$260.70
7 purchase totals =	$1,024.20		$1,105.4181	$1,105.41	$1,105.40	$1,105.50