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	$188.32	4.419%	$196.6419	$196.64	$196.65	$196.60
Purchase #2	$137.31	6.564%	$146.323	$146.32	$146.30	$146.30
Purchase #3	$178.64	13.525%	$202.8011	$202.80	$202.80	$202.80
Purchase #4	$136.25	11.516%	$151.9406	$151.94	$151.95	$151.90
Purchase #5	$142.47	13.611%	$161.8616	$161.86	$161.85	$161.90
Purchase #6	$69.91	9.437%	$76.5074	$76.51	$76.50	$76.50
Purchase #7	$70.36	11.808%	$78.6681	$78.67	$78.65	$78.70
7 purchase totals =	$923.26		$1,014.7437	$1,014.74	$1,014.70	$1,014.70