ActionScript 3.0 :: File Size And Loading Classes?

i have several custom classes which all contain Sprites.does the fact that each as file imports flash.display.Sprite increase file size?i would assume when compiling that flash is smart enough to just import each package once but i just want to make sure.an over simplified example (obviously in this example the over all effect is 0 but i am starting to have more and more custom classes so i want to know)say i have a simple class that extends sprite to include an index property.

public class NewSprite extends Sprite {
public var index:int
}

now if in my code i would like to have "Sprite"s and "NewSprite"s for my own benefit of keeping track of what needs an index but does it add to file size to import flash.graphics.Sprite twice or would i be better off just importing NewSprite.also if i add variables to a custom class but dont give them a value does it take up extra space - for instance if the above NewSprite had 99999 indices instead of 1 - i am assuming if each index has a value the NewSprite is much bigger, but if i leave each index null, does it still increase file size?