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	$176.65	13.434%	$200.3812	$200.38	$200.40	$200.40
Purchase #2	$12.75	4.346%	$13.3041	$13.30	$13.30	$13.30
Purchase #3	$90.40	13.831%	$102.9032	$102.90	$102.90	$102.90
Purchase #4	$147.33	12.818%	$166.2148	$166.21	$166.20	$166.20
Purchase #5	$178.69	9.721%	$196.0605	$196.06	$196.05	$196.10
Purchase #6	$187.46	3.439%	$193.9067	$193.91	$193.90	$193.90
Purchase #7	$140.55	7.180%	$150.6415	$150.64	$150.65	$150.60
7 purchase totals =	$933.83		$1,023.4120	$1,023.40	$1,023.40	$1,023.40