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	$182.33	7.406%	$195.8334	$195.83	$195.85	$195.80
Purchase #2	$70.57	11.148%	$78.4371	$78.44	$78.45	$78.40
Purchase #3	$56.69	7.568%	$60.9803	$60.98	$61.00	$61.00
Purchase #4	$152.35	11.510%	$169.8855	$169.89	$169.90	$169.90
Purchase #5	$168.57	3.617%	$174.6672	$174.67	$174.65	$174.70
Purchase #6	$95.51	6.868%	$102.0696	$102.07	$102.05	$102.10
Purchase #7	$226.31	6.735%	$241.552	$241.55	$241.55	$241.60
7 purchase totals =	$952.33		$1,023.4251	$1,023.43	$1,023.45	$1,023.50