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	$175.52	3.705%	$182.023	$182.02	$182.00	$182.00
Purchase #2	$78.82	3.638%	$81.6875	$81.69	$81.70	$81.70
Purchase #3	$124.78	12.275%	$140.0967	$140.10	$140.10	$140.10
Purchase #4	$210.80	3.328%	$217.8154	$217.82	$217.80	$217.80
Purchase #5	$232.50	12.444%	$261.4323	$261.43	$261.45	$261.40
Purchase #6	$119.71	6.165%	$127.0901	$127.09	$127.10	$127.10
Purchase #7	$32.57	13.872%	$37.0881	$37.09	$37.10	$37.10
7 purchase totals =	$974.70		$1,047.2331	$1,047.24	$1,047.25	$1,047.20