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	$182.62	8.113%	$197.436	$197.44	$197.45	$197.40
Purchase #2	$81.80	4.282%	$85.3027	$85.30	$85.30	$85.30
Purchase #3	$118.27	10.314%	$130.4684	$130.47	$130.45	$130.50
Purchase #4	$234.96	6.756%	$250.8339	$250.83	$250.85	$250.80
Purchase #5	$110.52	11.301%	$123.0099	$123.01	$123.00	$123.00
Purchase #6	$82.38	11.500%	$91.8537	$91.85	$91.85	$91.90
Purchase #7	$136.55	5.193%	$143.641	$143.64	$143.65	$143.60
7 purchase totals =	$947.10		$1,022.5456	$1,022.54	$1,022.55	$1,022.50