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	$206.81	3.782%	$214.6316	$214.63	$214.65	$214.60
Purchase #2	$217.91	7.624%	$234.5235	$234.52	$234.50	$234.50
Purchase #3	$7.53	4.223%	$7.848	$7.85	$7.85	$7.80
Purchase #4	$45.58	6.595%	$48.586	$48.59	$48.60	$48.60
Purchase #5	$95.26	3.196%	$98.3045	$98.30	$98.30	$98.30
Purchase #6	$181.25	10.761%	$200.7543	$200.75	$200.75	$200.80
Purchase #7	$196.60	5.744%	$207.8927	$207.89	$207.90	$207.90
7 purchase totals =	$950.94		$1,012.5406	$1,012.53	$1,012.55	$1,012.50