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	$158.42	10.343%	$174.8054	$174.81	$174.80	$174.80
Purchase #2	$171.71	12.107%	$192.4989	$192.50	$192.50	$192.50
Purchase #3	$104.71	6.144%	$111.1434	$111.14	$111.15	$111.10
Purchase #4	$160.39	8.525%	$174.0632	$174.06	$174.05	$174.10
Purchase #5	$168.98	3.844%	$175.4756	$175.48	$175.50	$175.50
Purchase #6	$94.40	5.714%	$99.794	$99.79	$99.80	$99.80
Purchase #7	$108.89	8.692%	$118.3547	$118.35	$118.35	$118.40
7 purchase totals =	$967.50		$1,046.1352	$1,046.13	$1,046.15	$1,046.20