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	$195.68	7.425%	$210.2092	$210.21	$210.20	$210.20
Purchase #2	$89.25	11.833%	$99.811	$99.81	$99.80	$99.80
Purchase #3	$13.74	12.175%	$15.4128	$15.41	$15.40	$15.40
Purchase #4	$176.85	4.285%	$184.428	$184.43	$184.45	$184.40
Purchase #5	$56.92	11.481%	$63.455	$63.46	$63.45	$63.50
Purchase #6	$211.48	5.435%	$222.9739	$222.97	$222.95	$223.00
Purchase #7	$225.42	5.662%	$238.1833	$238.18	$238.20	$238.20
7 purchase totals =	$969.34		$1,034.4732	$1,034.47	$1,034.45	$1,034.50