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	$152.37	13.493%	$172.9293	$172.93	$172.95	$172.90
Purchase #2	$213.76	13.450%	$242.5107	$242.51	$242.50	$242.50
Purchase #3	$191.66	13.530%	$217.5916	$217.59	$217.60	$217.60
Purchase #4	$35.50	4.276%	$37.018	$37.02	$37.00	$37.00
Purchase #5	$5.79	11.420%	$6.4512	$6.45	$6.45	$6.50
Purchase #6	$72.32	3.729%	$75.0168	$75.02	$75.00	$75.00
Purchase #7	$181.41	10.608%	$200.654	$200.65	$200.65	$200.70
7 purchase totals =	$852.81		$952.1716	$952.17	$952.15	$952.20