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	$118.75	5.636%	$125.4428	$125.44	$125.45	$125.40
Purchase #2	$204.82	7.436%	$220.0504	$220.05	$220.05	$220.10
Purchase #3	$69.91	4.282%	$72.9035	$72.90	$72.90	$72.90
Purchase #4	$182.86	6.532%	$194.8044	$194.80	$194.80	$194.80
Purchase #5	$96.35	3.620%	$99.8379	$99.84	$99.85	$99.80
Purchase #6	$146.64	12.650%	$165.19	$165.19	$165.20	$165.20
Purchase #7	$171.80	6.693%	$183.2986	$183.30	$183.30	$183.30
7 purchase totals =	$991.13		$1,061.5276	$1,061.52	$1,061.55	$1,061.50