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	$222.86	10.281%	$245.7722	$245.77	$245.75	$245.80
Purchase #2	$68.91	5.773%	$72.8882	$72.89	$72.90	$72.90
Purchase #3	$83.30	5.532%	$87.9082	$87.91	$87.90	$87.90
Purchase #4	$181.26	4.650%	$189.6886	$189.69	$189.70	$189.70
Purchase #5	$56.55	13.360%	$64.1051	$64.11	$64.10	$64.10
Purchase #6	$182.71	13.627%	$207.6079	$207.61	$207.60	$207.60
Purchase #7	$137.79	6.384%	$146.5865	$146.59	$146.60	$146.60
7 purchase totals =	$933.38		$1,014.5567	$1,014.57	$1,014.55	$1,014.60