You don't need to take the cutting during flower to get the bushy effect. I have one clone now that accidently went into flower last April and she's still revegging now (almost done). She wasn't showing flowers at the time but started showing after I moved her back to 16 hours. She's definitely bushier than the mother, in my opinion too bushy. She'll need a lot of thinning if I ever decide to put her in production. For now she's a clone mother (my original plan for her).
The other plants that I moved in time to avoid flowering are over twice as large as her. If I had been training them for the last 2 months I think they would still be larger and have much better structure for quality yield. Point A) Revegging at any time in life cycle results in bushier plant, likely due to stress shortening nodes. I noticed on two other plants I revegged that they also produced new shoots between nodes (weak tiny shoots, not productive). B) Factoring in time involved I don't think there is any gain and may be a net loss in productive potential.
That said, it's still worth trying for the fun of it plus the knowledge gained by observing different ways plants grow. I don't know if there's any long term damage to plants from revegging. I'm going to let my reveg girl grow naturally all summer (probably until I forget to move her under lights and she 'accidently' goes into flower again.) It will be interesting if she goes back to business as usual or if she stays extra bushy.
And 20 years of clones?! Holy Cannabis, Batman!