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	$162.29	12.190%	$182.0732	$182.07	$182.05	$182.10
Purchase #2	$12.85	4.776%	$13.4637	$13.46	$13.45	$13.50
Purchase #3	$55.51	3.331%	$57.359	$57.36	$57.35	$57.40
Purchase #4	$162.77	5.329%	$171.444	$171.44	$171.45	$171.40
Purchase #5	$184.48	10.334%	$203.5442	$203.54	$203.55	$203.50
Purchase #6	$238.67	9.704%	$261.8305	$261.83	$261.85	$261.80
Purchase #7	$241.94	5.242%	$254.6225	$254.62	$254.60	$254.60
7 purchase totals =	$1,058.51		$1,144.3371	$1,144.32	$1,144.30	$1,144.30