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	$196.84	10.121%	$216.7622	$216.76	$216.75	$216.80
Purchase #2	$100.46	11.372%	$111.8843	$111.88	$111.90	$111.90
Purchase #3	$14.88	5.431%	$15.6881	$15.69	$15.70	$15.70
Purchase #4	$180.78	12.353%	$203.1118	$203.11	$203.10	$203.10
Purchase #5	$111.79	5.861%	$118.342	$118.34	$118.35	$118.30
Purchase #6	$179.90	7.173%	$192.8042	$192.80	$192.80	$192.80
Purchase #7	$212.92	11.792%	$238.0275	$238.03	$238.05	$238.00
7 purchase totals =	$997.57		$1,096.6201	$1,096.61	$1,096.65	$1,096.60