But I have the Pin set high if the button is not pressed. so Why it should not be counted when its low?
600ms is because I don't want to allow the button being pressed that frequently.
That means you're debouncing the user, not the switch. If you use the state change detection approach you only act when the state of the switch changes. The user could hold it down for minutes and it will only count once. When you simply check the state of the switch you increment the counter every time it checks, if the switch is pressed. Your work around is the long delay giving the user time to release the switch. This is debouncing the user. I used to do that until I figured it out.