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	$192.94	4.605%	$201.8249	$201.82	$201.80	$201.80
Purchase #2	$5.88	5.630%	$6.211	$6.21	$6.20	$6.20
Purchase #3	$125.92	11.586%	$140.5091	$140.51	$140.50	$140.50
Purchase #4	$175.57	11.847%	$196.3698	$196.37	$196.35	$196.40
Purchase #5	$192.44	4.301%	$200.7168	$200.72	$200.70	$200.70
Purchase #6	$237.40	5.840%	$251.2642	$251.26	$251.25	$251.30
Purchase #7	$59.40	8.705%	$64.5708	$64.57	$64.55	$64.60
7 purchase totals =	$989.55		$1,061.4666	$1,061.46	$1,061.35	$1,061.50