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	$98.32	13.859%	$111.9462	$111.95	$111.95	$111.90
Purchase #2	$176.52	11.381%	$196.6097	$196.61	$196.60	$196.60
Purchase #3	$241.39	7.682%	$259.9336	$259.93	$259.95	$259.90
Purchase #4	$28.48	4.369%	$29.7243	$29.72	$29.70	$29.70
Purchase #5	$165.80	7.380%	$178.036	$178.04	$178.05	$178.00
Purchase #6	$24.39	7.832%	$26.3002	$26.30	$26.30	$26.30
Purchase #7	$250.77	9.478%	$274.538	$274.54	$274.55	$274.50
7 purchase totals =	$985.67		$1,077.0880	$1,077.09	$1,077.10	$1,076.90