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	$118.35	6.436%	$125.967	$125.97	$125.95	$126.00
Purchase #2	$75.63	6.352%	$80.434	$80.43	$80.45	$80.40
Purchase #3	$165.92	8.116%	$179.3861	$179.39	$179.40	$179.40
Purchase #4	$91.56	4.298%	$95.4952	$95.50	$95.50	$95.50
Purchase #5	$239.89	8.874%	$261.1778	$261.18	$261.20	$261.20
Purchase #6	$67.83	6.345%	$72.1338	$72.13	$72.15	$72.10
Purchase #7	$145.53	7.757%	$156.8188	$156.82	$156.80	$156.80
7 purchase totals =	$904.71		$971.4127	$971.42	$971.45	$971.40