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	$196.43	7.239%	$210.6496	$210.65	$210.65	$210.60
Purchase #2	$212.31	13.258%	$240.4581	$240.46	$240.45	$240.50
Purchase #3	$5.76	3.509%	$5.9621	$5.96	$5.95	$6.00
Purchase #4	$85.32	6.385%	$90.7677	$90.77	$90.75	$90.80
Purchase #5	$128.45	11.304%	$142.97	$142.97	$142.95	$143.00
Purchase #6	$150.31	11.481%	$167.5671	$167.57	$167.55	$167.60
Purchase #7	$192.72	12.601%	$217.0046	$217.00	$217.00	$217.00
7 purchase totals =	$971.30		$1,075.3792	$1,075.38	$1,075.30	$1,075.50