When can front line release downfield on punts?

[rocketballz]

In the spread formation on punts, when can the front line release downfield toward returner. Do they have to wait for the ball to be kicked or can it be immediate. I have seen the front line just go on snap, especially when using the shield formation in the past. What is the correct call?

 

[White hat]

Whenever they want to go.

The NFL is the only set of rules requiring the line to wait for the kick.

 

[FBRef]

Another one of those Sunday rules that isn't a rule on Friday night.