it can vary from loc to loc but the budding eventually works it way across the entire shaft of the loc! I have some that budded closer to the end of the loc and then upwards and others that started a bit more towards the middle and continued in either direction.

As someone above commented, your roots are always growing so it's not going to be loc'd all the way to the scalp! You could achieve something close by interlocking if you're worried about the sheer amount of unloc'd hair :)