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	$183.64	9.462%	$201.016	$201.02	$201.00	$201.00
Purchase #2	$92.78	4.467%	$96.9245	$96.92	$96.90	$96.90
Purchase #3	$84.76	13.471%	$96.178	$96.18	$96.20	$96.20
Purchase #4	$73.89	5.682%	$78.0884	$78.09	$78.10	$78.10
Purchase #5	$219.86	10.223%	$242.3363	$242.34	$242.35	$242.30
Purchase #6	$36.94	3.720%	$38.3142	$38.31	$38.30	$38.30
Purchase #7	$249.67	12.513%	$280.9112	$280.91	$280.90	$280.90
7 purchase totals =	$941.54		$1,033.7686	$1,033.77	$1,033.75	$1,033.70