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	$211.94	7.346%	$227.5091	$227.51	$227.50	$227.50
Purchase #2	$62.73	7.714%	$67.569	$67.57	$67.55	$67.60
Purchase #3	$227.71	8.831%	$247.8191	$247.82	$247.80	$247.80
Purchase #4	$181.90	5.382%	$191.6899	$191.69	$191.70	$191.70
Purchase #5	$124.98	13.795%	$142.221	$142.22	$142.20	$142.20
Purchase #6	$73.76	13.696%	$83.8622	$83.86	$83.85	$83.90
Purchase #7	$81.61	13.749%	$92.8306	$92.83	$92.85	$92.80
7 purchase totals =	$964.63		$1,053.5009	$1,053.50	$1,053.45	$1,053.50