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	$181.95	8.737%	$197.847	$197.85	$197.85	$197.80
Purchase #2	$241.34	13.364%	$273.5927	$273.59	$273.60	$273.60
Purchase #3	$25.37	8.742%	$27.5878	$27.59	$27.60	$27.60
Purchase #4	$212.28	5.704%	$224.3885	$224.39	$224.40	$224.40
Purchase #5	$30.69	3.826%	$31.8642	$31.86	$31.85	$31.90
Purchase #6	$127.45	12.198%	$142.9964	$143.00	$143.00	$143.00
Purchase #7	$119.59	6.736%	$127.6456	$127.65	$127.65	$127.60
7 purchase totals =	$938.67		$1,025.9222	$1,025.93	$1,025.95	$1,025.90