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	$231.33	6.583%	$246.5585	$246.56	$246.55	$246.60
Purchase #2	$117.86	11.575%	$131.5023	$131.50	$131.50	$131.50
Purchase #3	$70.55	4.400%	$73.6542	$73.65	$73.65	$73.70
Purchase #4	$25.88	9.591%	$28.3622	$28.36	$28.35	$28.40
Purchase #5	$215.92	10.550%	$238.6996	$238.70	$238.70	$238.70
Purchase #6	$123.94	10.663%	$137.1557	$137.16	$137.15	$137.20
Purchase #7	$160.69	3.493%	$166.3029	$166.30	$166.30	$166.30
7 purchase totals =	$946.17		$1,022.2354	$1,022.23	$1,022.20	$1,022.40