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	$105.41	5.238%	$110.9314	$110.93	$110.95	$110.90
Purchase #2	$221.41	8.170%	$239.4992	$239.50	$239.50	$239.50
Purchase #3	$100.89	4.328%	$105.2565	$105.26	$105.25	$105.30
Purchase #4	$107.67	7.843%	$116.1146	$116.11	$116.10	$116.10
Purchase #5	$158.46	4.721%	$165.9409	$165.94	$165.95	$165.90
Purchase #6	$158.57	6.500%	$168.8771	$168.88	$168.90	$168.90
Purchase #7	$93.98	11.633%	$104.9127	$104.91	$104.90	$104.90
7 purchase totals =	$946.39		$1,011.5324	$1,011.53	$1,011.55	$1,011.50