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	$227.66	7.463%	$244.6503	$244.65	$244.65	$244.70
Purchase #2	$88.73	7.176%	$95.0973	$95.10	$95.10	$95.10
Purchase #3	$119.57	6.166%	$126.9427	$126.94	$126.95	$126.90
Purchase #4	$181.91	3.300%	$187.913	$187.91	$187.90	$187.90
Purchase #5	$228.30	7.506%	$245.4362	$245.44	$245.45	$245.40
Purchase #6	$86.25	4.400%	$90.045	$90.05	$90.05	$90.00
Purchase #7	$143.48	7.523%	$154.274	$154.27	$154.25	$154.30
7 purchase totals =	$1,075.90		$1,144.3585	$1,144.36	$1,144.35	$1,144.30