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	$219.42	3.397%	$226.8737	$226.87	$226.85	$226.90
Purchase #2	$87.61	13.577%	$99.5048	$99.50	$99.50	$99.50
Purchase #3	$6.81	3.715%	$7.063	$7.06	$7.05	$7.10
Purchase #4	$206.31	12.709%	$232.5299	$232.53	$232.55	$232.50
Purchase #5	$198.73	10.538%	$219.6722	$219.67	$219.65	$219.70
Purchase #6	$109.51	3.623%	$113.4775	$113.48	$113.50	$113.50
Purchase #7	$111.93	10.398%	$123.5685	$123.57	$123.55	$123.60
7 purchase totals =	$940.32		$1,022.6896	$1,022.68	$1,022.65	$1,022.80