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	$199.47	7.530%	$214.4901	$214.49	$214.50	$214.50
Purchase #2	$37.71	5.409%	$39.7497	$39.75	$39.75	$39.70
Purchase #3	$61.52	6.411%	$65.464	$65.46	$65.45	$65.50
Purchase #4	$146.38	12.403%	$164.5355	$164.54	$164.55	$164.50
Purchase #5	$19.27	10.354%	$21.2652	$21.27	$21.25	$21.30
Purchase #6	$16.43	10.405%	$18.1395	$18.14	$18.15	$18.10
Purchase #7	$246.54	9.796%	$270.6911	$270.69	$270.70	$270.70
7 purchase totals =	$727.32		$794.3351	$794.34	$794.35	$794.30