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	$212.26	10.848%	$235.286	$235.29	$235.30	$235.30
Purchase #2	$42.39	3.466%	$43.8592	$43.86	$43.85	$43.90
Purchase #3	$208.52	3.751%	$216.3416	$216.34	$216.35	$216.30
Purchase #4	$227.28	5.129%	$238.9372	$238.94	$238.95	$238.90
Purchase #5	$225.54	5.185%	$237.2342	$237.23	$237.25	$237.20
Purchase #6	$45.97	4.837%	$48.1936	$48.19	$48.20	$48.20
Purchase #7	$54.51	12.192%	$61.1559	$61.16	$61.15	$61.20
7 purchase totals =	$1,016.47		$1,081.0077	$1,081.01	$1,081.05	$1,081.00