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	$217.29	8.466%	$235.6858	$235.69	$235.70	$235.70
Purchase #2	$102.96	8.346%	$111.553	$111.55	$111.55	$111.60
Purchase #3	$103.26	7.631%	$111.1398	$111.14	$111.15	$111.10
Purchase #4	$177.64	9.719%	$194.9048	$194.90	$194.90	$194.90
Purchase #5	$47.75	7.520%	$51.3408	$51.34	$51.35	$51.30
Purchase #6	$184.87	13.869%	$210.5096	$210.51	$210.50	$210.50
Purchase #7	$217.74	6.157%	$231.1463	$231.15	$231.15	$231.10
7 purchase totals =	$1,051.51		$1,146.2801	$1,146.28	$1,146.30	$1,146.20