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	$219.55	11.513%	$244.8268	$244.83	$244.85	$244.80
Purchase #2	$240.78	6.107%	$255.4844	$255.48	$255.50	$255.50
Purchase #3	$92.31	6.624%	$98.4246	$98.42	$98.40	$98.40
Purchase #4	$183.69	9.158%	$200.5123	$200.51	$200.50	$200.50
Purchase #5	$145.98	10.799%	$161.7444	$161.74	$161.75	$161.70
Purchase #6	$211.57	5.580%	$223.3756	$223.38	$223.40	$223.40
Purchase #7	$238.83	8.769%	$259.773	$259.77	$259.75	$259.80
7 purchase totals =	$1,332.71		$1,444.1411	$1,444.13	$1,444.15	$1,444.10