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	$37.48	10.337%	$41.3543	$41.35	$41.35	$41.40
Purchase #2	$207.39	4.130%	$215.9552	$215.96	$215.95	$216.00
Purchase #3	$212.54	7.624%	$228.744	$228.74	$228.75	$228.70
Purchase #4	$194.41	12.431%	$218.5771	$218.58	$218.60	$218.60
Purchase #5	$65.93	9.688%	$72.3173	$72.32	$72.30	$72.30
Purchase #6	$91.53	4.487%	$95.637	$95.64	$95.65	$95.60
Purchase #7	$139.56	3.500%	$144.4446	$144.44	$144.45	$144.40
7 purchase totals =	$948.84		$1,017.0295	$1,017.03	$1,017.05	$1,017.00