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	$184.36	6.348%	$196.0632	$196.06	$196.05	$196.10
Purchase #2	$174.35	4.676%	$182.5026	$182.50	$182.50	$182.50
Purchase #3	$144.58	12.373%	$162.4689	$162.47	$162.45	$162.50
Purchase #4	$63.59	4.152%	$66.2303	$66.23	$66.25	$66.20
Purchase #5	$166.68	3.585%	$172.6555	$172.66	$172.65	$172.70
Purchase #6	$189.69	11.162%	$210.8632	$210.86	$210.85	$210.90
Purchase #7	$97.90	7.307%	$105.0536	$105.05	$105.05	$105.10
7 purchase totals =	$1,021.15		$1,095.8373	$1,095.83	$1,095.80	$1,096.00