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	$84.49	9.575%	$92.5799	$92.58	$92.60	$92.60
Purchase #2	$92.58	9.725%	$101.5834	$101.58	$101.60	$101.60
Purchase #3	$178.93	4.598%	$187.1572	$187.16	$187.15	$187.20
Purchase #4	$236.82	13.552%	$268.9138	$268.91	$268.90	$268.90
Purchase #5	$202.87	8.122%	$219.3471	$219.35	$219.35	$219.30
Purchase #6	$28.31	5.526%	$29.8744	$29.87	$29.85	$29.90
Purchase #7	$189.87	3.524%	$196.561	$196.56	$196.55	$196.60
7 purchase totals =	$1,013.87		$1,096.0168	$1,096.01	$1,096.00	$1,096.10