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	$195.81	6.797%	$209.1192	$209.12	$209.10	$209.10
Purchase #2	$166.32	11.406%	$185.2905	$185.29	$185.30	$185.30
Purchase #3	$63.81	8.540%	$69.2594	$69.26	$69.25	$69.30
Purchase #4	$188.72	13.384%	$213.9783	$213.98	$214.00	$214.00
Purchase #5	$22.51	10.451%	$24.8625	$24.86	$24.85	$24.90
Purchase #6	$127.61	13.216%	$144.4749	$144.47	$144.45	$144.50
Purchase #7	$163.48	13.679%	$185.8424	$185.84	$185.85	$185.80
7 purchase totals =	$928.26		$1,032.8272	$1,032.82	$1,032.80	$1,032.90