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	$176.48	11.467%	$196.717	$196.72	$196.70	$196.70
Purchase #2	$36.34	5.645%	$38.3914	$38.39	$38.40	$38.40
Purchase #3	$110.59	11.595%	$123.4129	$123.41	$123.40	$123.40
Purchase #4	$128.57	4.562%	$134.4354	$134.44	$134.45	$134.40
Purchase #5	$149.48	9.615%	$163.8525	$163.85	$163.85	$163.90
Purchase #6	$176.50	12.404%	$198.3931	$198.39	$198.40	$198.40
Purchase #7	$116.60	9.163%	$127.2841	$127.28	$127.30	$127.30
7 purchase totals =	$894.56		$982.4864	$982.48	$982.50	$982.50