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	$194.86	7.666%	$209.798	$209.80	$209.80	$209.80
Purchase #2	$55.94	10.616%	$61.8786	$61.88	$61.90	$61.90
Purchase #3	$154.66	4.272%	$161.2671	$161.27	$161.25	$161.30
Purchase #4	$159.87	3.186%	$164.9635	$164.96	$164.95	$165.00
Purchase #5	$120.31	4.174%	$125.3317	$125.33	$125.35	$125.30
Purchase #6	$196.39	12.784%	$221.4965	$221.50	$221.50	$221.50
Purchase #7	$66.46	8.108%	$71.8486	$71.85	$71.85	$71.80
7 purchase totals =	$948.49		$1,016.5840	$1,016.59	$1,016.60	$1,016.60