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	$105.76	3.593%	$109.56	$109.56	$109.55	$109.60
Purchase #2	$58.86	4.561%	$61.5446	$61.54	$61.55	$61.50
Purchase #3	$158.89	9.747%	$174.377	$174.38	$174.40	$174.40
Purchase #4	$160.63	5.575%	$169.5851	$169.59	$169.60	$169.60
Purchase #5	$185.66	10.352%	$204.8795	$204.88	$204.90	$204.90
Purchase #6	$177.75	10.838%	$197.0145	$197.01	$197.00	$197.00
Purchase #7	$105.67	6.349%	$112.379	$112.38	$112.40	$112.40
7 purchase totals =	$953.22		$1,029.3397	$1,029.34	$1,029.40	$1,029.40