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	$84.54	12.355%	$94.9849	$94.98	$95.00	$95.00
Purchase #2	$235.86	8.173%	$255.1368	$255.14	$255.15	$255.10
Purchase #3	$242.68	5.135%	$255.1416	$255.14	$255.15	$255.10
Purchase #4	$102.93	13.814%	$117.1488	$117.15	$117.15	$117.10
Purchase #5	$108.66	3.572%	$112.5413	$112.54	$112.55	$112.50
Purchase #6	$249.57	7.835%	$269.1238	$269.12	$269.10	$269.10
Purchase #7	$139.93	11.224%	$155.6357	$155.64	$155.65	$155.60
7 purchase totals =	$1,164.17		$1,259.7129	$1,259.71	$1,259.75	$1,259.50