Originally Posted by drakulie
No. Just different. That said, if you do this on the crosses, you will achieve a tighter string bed.
More than likely you are correct but not for the reason you are insinuating. When you pull twice you are doing something to break the friction between the mains and crosses. When that friction is overcome more of the tension is applied to the complete cross string.
When I pull tension on a cross (using a constant pull) if first move the string I am tensioning to try to get it close to straight. It's breaks the friction between that cross and the mains. Ten I straighten the last cross I tensioned to get it as straight as I can. Then I move that string I am tensioning again. All this takes time and that extra time I use stretches the cross string for a longer period of time which produces a tighter string bed. With the mains that isn't necessary because there are no crosses in yet but a slight tug on the string you are tension could break the friction between the main and the frame again making for a tighter string bed all without rally increasing tension.
None of this is necessary with an electronic constant pull that produces a jerky (off-on-off) pull on the string which breaks the friction.