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	$229.64	5.199%	$241.579	$241.58	$241.60	$241.60
Purchase #2	$51.34	4.451%	$53.6251	$53.63	$53.65	$53.60
Purchase #3	$239.83	9.248%	$262.0095	$262.01	$262.00	$262.00
Purchase #4	$175.94	13.421%	$199.5529	$199.55	$199.55	$199.60
Purchase #5	$204.49	9.489%	$223.8941	$223.89	$223.90	$223.90
Purchase #6	$42.28	3.621%	$43.811	$43.81	$43.80	$43.80
Purchase #7	$216.33	13.152%	$244.7817	$244.78	$244.80	$244.80
7 purchase totals =	$1,159.85		$1,269.2533	$1,269.25	$1,269.30	$1,269.30