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	$185.70	9.563%	$203.4585	$203.46	$203.45	$203.50
Purchase #2	$10.65	6.710%	$11.3646	$11.36	$11.35	$11.40
Purchase #3	$224.46	8.806%	$244.2259	$244.23	$244.25	$244.20
Purchase #4	$206.65	8.662%	$224.55	$224.55	$224.55	$224.60
Purchase #5	$205.64	11.648%	$229.5929	$229.59	$229.60	$229.60
Purchase #6	$235.28	8.212%	$254.6012	$254.60	$254.60	$254.60
Purchase #7	$27.34	4.617%	$28.6023	$28.60	$28.60	$28.60
7 purchase totals =	$1,095.72		$1,196.3954	$1,196.39	$1,196.40	$1,196.50