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	$195.69	10.709%	$216.6464	$216.65	$216.65	$216.60
Purchase #2	$148.91	10.763%	$164.9372	$164.94	$164.95	$164.90
Purchase #3	$65.44	6.572%	$69.7407	$69.74	$69.75	$69.70
Purchase #4	$191.83	4.719%	$200.8825	$200.88	$200.90	$200.90
Purchase #5	$96.45	6.680%	$102.8929	$102.89	$102.90	$102.90
Purchase #6	$85.80	4.283%	$89.4748	$89.47	$89.45	$89.50
Purchase #7	$208.96	4.503%	$218.3695	$218.37	$218.35	$218.40
7 purchase totals =	$993.08		$1,062.9440	$1,062.94	$1,062.95	$1,062.90