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	$233.96	12.335%	$262.819	$262.82	$262.80	$262.80
Purchase #2	$16.48	11.290%	$18.3406	$18.34	$18.35	$18.30
Purchase #3	$94.36	13.389%	$106.9939	$106.99	$107.00	$107.00
Purchase #4	$29.53	9.359%	$32.2937	$32.29	$32.30	$32.30
Purchase #5	$185.61	10.685%	$205.4424	$205.44	$205.45	$205.40
Purchase #6	$180.59	6.644%	$192.5884	$192.59	$192.60	$192.60
Purchase #7	$200.52	11.283%	$223.1447	$223.14	$223.15	$223.10
7 purchase totals =	$941.05		$1,041.6227	$1,041.61	$1,041.65	$1,041.50