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	$195.88	11.597%	$218.5962	$218.60	$218.60	$218.60
Purchase #2	$97.74	5.144%	$102.7677	$102.77	$102.75	$102.80
Purchase #3	$63.28	6.104%	$67.1426	$67.14	$67.15	$67.10
Purchase #4	$196.74	13.671%	$223.6363	$223.64	$223.65	$223.60
Purchase #5	$200.43	5.111%	$210.674	$210.67	$210.65	$210.70
Purchase #6	$32.54	9.210%	$35.5369	$35.54	$35.55	$35.50
Purchase #7	$177.50	10.479%	$196.1002	$196.10	$196.10	$196.10
7 purchase totals =	$964.11		$1,054.4539	$1,054.46	$1,054.45	$1,054.40