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	$181.89	7.776%	$196.0338	$196.03	$196.05	$196.00
Purchase #2	$170.51	6.163%	$181.0185	$181.02	$181.00	$181.00
Purchase #3	$76.87	6.483%	$81.8535	$81.85	$81.85	$81.90
Purchase #4	$205.36	13.158%	$232.3813	$232.38	$232.40	$232.40
Purchase #5	$64.27	12.639%	$72.3931	$72.39	$72.40	$72.40
Purchase #6	$167.86	7.693%	$180.7735	$180.77	$180.75	$180.80
Purchase #7	$10.96	6.183%	$11.6377	$11.64	$11.65	$11.60
7 purchase totals =	$877.72		$956.0914	$956.08	$956.10	$956.10