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	$190.59	7.631%	$205.1339	$205.13	$205.15	$205.10
Purchase #2	$162.51	6.206%	$172.5954	$172.60	$172.60	$172.60
Purchase #3	$228.84	7.463%	$245.9183	$245.92	$245.90	$245.90
Purchase #4	$223.96	7.624%	$241.0347	$241.03	$241.05	$241.00
Purchase #5	$229.39	11.250%	$255.1964	$255.20	$255.20	$255.20
Purchase #6	$185.67	7.357%	$199.3297	$199.33	$199.35	$199.30
Purchase #7	$142.80	5.531%	$150.6983	$150.70	$150.70	$150.70
7 purchase totals =	$1,363.76		$1,469.9067	$1,469.91	$1,469.95	$1,469.80