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	$68.87	5.400%	$72.589	$72.59	$72.60	$72.60
Purchase #2	$55.45	11.674%	$61.9232	$61.92	$61.90	$61.90
Purchase #3	$85.92	9.528%	$94.1065	$94.11	$94.10	$94.10
Purchase #4	$176.73	7.736%	$190.4018	$190.40	$190.40	$190.40
Purchase #5	$141.96	11.719%	$158.5963	$158.60	$158.60	$158.60
Purchase #6	$206.63	4.544%	$216.0193	$216.02	$216.00	$216.00
Purchase #7	$230.85	3.379%	$238.6504	$238.65	$238.65	$238.70
7 purchase totals =	$966.41		$1,032.2865	$1,032.29	$1,032.25	$1,032.30