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	$88.76	7.538%	$95.4507	$95.45	$95.45	$95.50
Purchase #2	$131.94	9.222%	$144.1075	$144.11	$144.10	$144.10
Purchase #3	$177.71	13.637%	$201.9443	$201.94	$201.95	$201.90
Purchase #4	$111.99	4.850%	$117.4215	$117.42	$117.40	$117.40
Purchase #5	$88.65	12.155%	$99.4254	$99.43	$99.45	$99.40
Purchase #6	$200.32	6.536%	$213.4129	$213.41	$213.40	$213.40
Purchase #7	$178.64	3.196%	$184.3493	$184.35	$184.35	$184.30
7 purchase totals =	$978.01		$1,056.1116	$1,056.11	$1,056.10	$1,056.00