Sure, there are both costs and benefits to this, which is why you should only do it when the benefits clearly are bigger than the costs.

Not every time your function line count is > 10, as I heard from some crazy company a friend worked for...

I prefer to put the broken out function(s) immediately below the main one for a logical reading experience: Overview first, details below if needed.

Comments are of course good when they are current and correct. But they rarely stay that way for long...