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	$56.27	3.853%	$58.4381	$58.44	$58.45	$58.40
Purchase #2	$208.33	13.773%	$237.0233	$237.02	$237.00	$237.00
Purchase #3	$69.45	4.791%	$72.7773	$72.78	$72.80	$72.80
Purchase #4	$188.31	4.779%	$197.3093	$197.31	$197.30	$197.30
Purchase #5	$90.59	10.723%	$100.304	$100.30	$100.30	$100.30
Purchase #6	$213.57	12.182%	$239.5871	$239.59	$239.60	$239.60
Purchase #7	$105.84	3.432%	$109.4724	$109.47	$109.45	$109.50
7 purchase totals =	$932.36		$1,014.9115	$1,014.91	$1,014.90	$1,014.90