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	$219.29	7.482%	$235.6973	$235.70	$235.70	$235.70
Purchase #2	$71.85	9.787%	$78.882	$78.88	$78.90	$78.90
Purchase #3	$196.73	11.421%	$219.1985	$219.20	$219.20	$219.20
Purchase #4	$165.35	5.753%	$174.8626	$174.86	$174.85	$174.90
Purchase #5	$190.86	10.262%	$210.4461	$210.45	$210.45	$210.40
Purchase #6	$12.65	11.162%	$14.062	$14.06	$14.05	$14.10
Purchase #7	$212.37	4.483%	$221.8905	$221.89	$221.90	$221.90
7 purchase totals =	$1,069.10		$1,155.0390	$1,155.04	$1,155.05	$1,155.10