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	$59.56	5.344%	$62.7429	$62.74	$62.75	$62.70
Purchase #2	$246.39	8.231%	$266.6704	$266.67	$266.65	$266.70
Purchase #3	$205.85	6.256%	$218.728	$218.73	$218.75	$218.70
Purchase #4	$27.53	7.268%	$29.5309	$29.53	$29.55	$29.50
Purchase #5	$147.69	7.467%	$158.718	$158.72	$158.70	$158.70
Purchase #6	$219.32	13.330%	$248.5554	$248.56	$248.55	$248.60
Purchase #7	$54.89	8.529%	$59.5716	$59.57	$59.55	$59.60
7 purchase totals =	$961.23		$1,044.5172	$1,044.52	$1,044.50	$1,044.50