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	$200.88	4.609%	$210.1386	$210.14	$210.15	$210.10
Purchase #2	$11.92	12.860%	$13.4529	$13.45	$13.45	$13.50
Purchase #3	$216.62	3.199%	$223.5497	$223.55	$223.55	$223.50
Purchase #4	$136.71	10.831%	$151.5171	$151.52	$151.50	$151.50
Purchase #5	$8.59	7.681%	$9.2498	$9.25	$9.25	$9.20
Purchase #6	$217.29	9.246%	$237.3806	$237.38	$237.40	$237.40
Purchase #7	$164.78	4.786%	$172.6664	$172.67	$172.65	$172.70
7 purchase totals =	$956.79		$1,017.9551	$1,017.96	$1,017.95	$1,017.90