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	$13.65	4.460%	$14.2588	$14.26	$14.25	$14.30
Purchase #2	$56.74	11.576%	$63.3082	$63.31	$63.30	$63.30
Purchase #3	$119.52	3.559%	$123.7737	$123.77	$123.75	$123.80
Purchase #4	$182.33	4.867%	$191.204	$191.20	$191.20	$191.20
Purchase #5	$102.89	8.446%	$111.5801	$111.58	$111.60	$111.60
Purchase #6	$181.90	7.438%	$195.4297	$195.43	$195.45	$195.40
Purchase #7	$49.88	6.825%	$53.2843	$53.28	$53.30	$53.30
7 purchase totals =	$706.91		$752.8388	$752.83	$752.85	$752.90