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	$188.43	9.693%	$206.6945	$206.69	$206.70	$206.70
Purchase #2	$226.41	13.242%	$256.3912	$256.39	$256.40	$256.40
Purchase #3	$92.86	11.607%	$103.6383	$103.64	$103.65	$103.60
Purchase #4	$248.97	3.548%	$257.8035	$257.80	$257.80	$257.80
Purchase #5	$153.53	3.553%	$158.9849	$158.98	$159.00	$159.00
Purchase #6	$240.51	6.665%	$256.54	$256.54	$256.55	$256.50
Purchase #7	$215.82	3.148%	$222.614	$222.61	$222.60	$222.60
7 purchase totals =	$1,366.53		$1,462.6664	$1,462.65	$1,462.70	$1,462.60