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	$69.67	4.743%	$72.9744	$72.97	$72.95	$73.00
Purchase #2	$202.91	3.500%	$210.0119	$210.01	$210.00	$210.00
Purchase #3	$146.37	3.262%	$151.1446	$151.14	$151.15	$151.10
Purchase #4	$89.65	8.632%	$97.3886	$97.39	$97.40	$97.40
Purchase #5	$175.90	5.595%	$185.7416	$185.74	$185.75	$185.70
Purchase #6	$129.56	6.240%	$137.6445	$137.64	$137.65	$137.60
Purchase #7	$189.98	8.673%	$206.457	$206.46	$206.45	$206.50
7 purchase totals =	$1,004.04		$1,061.3626	$1,061.35	$1,061.35	$1,061.30