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	$197.98	9.675%	$217.1346	$217.13	$217.15	$217.10
Purchase #2	$190.85	9.183%	$208.3758	$208.38	$208.40	$208.40
Purchase #3	$11.41	13.279%	$12.9251	$12.93	$12.95	$12.90
Purchase #4	$90.34	9.353%	$98.7895	$98.79	$98.80	$98.80
Purchase #5	$168.66	11.684%	$188.3662	$188.37	$188.35	$188.40
Purchase #6	$50.78	7.235%	$54.4539	$54.45	$54.45	$54.50
Purchase #7	$230.33	6.621%	$245.5801	$245.58	$245.60	$245.60
7 purchase totals =	$940.35		$1,025.6252	$1,025.63	$1,025.70	$1,025.70