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	$197.75	9.510%	$216.556	$216.56	$216.55	$216.60
Purchase #2	$200.62	5.212%	$211.0763	$211.08	$211.10	$211.10
Purchase #3	$12.93	7.202%	$13.8612	$13.86	$13.85	$13.90
Purchase #4	$116.90	12.381%	$131.3734	$131.37	$131.35	$131.40
Purchase #5	$231.51	13.735%	$263.3079	$263.31	$263.30	$263.30
Purchase #6	$196.93	7.725%	$212.1428	$212.14	$212.15	$212.10
Purchase #7	$59.99	9.658%	$65.7838	$65.78	$65.80	$65.80
7 purchase totals =	$1,016.63		$1,114.1014	$1,114.10	$1,114.10	$1,114.20