Performance is a psychological and spiritual initiative, and not just an astrological expression of latent yogas. In my professional sessions, I always prefer to address the obvious with very objective models that can produce measurable results. When that argument is understood, then I offer my insights from the other side; the astrological and metaphysical. This gives my client a fuller view of the probable energies clouding over him and what he can probably do about managing things better.
Has the simple question been asked? Where did he screw up? Why did he screw up? Why does he keep on tripping over or stepping on people's toes or almost always missing out on things? Is he clear about his role, was he supplied the competency to deliver, were the right tools in hand? Were the targets realistic? These should be asked first before asking "I think Mercury was retrograde when that screw up started and the whole thing exploded when it went stationary two days later before going direct again the next few days". I remember how I used to do things contrary to what my thithi would indicate for my productivity on any particular day just to see the effects of my experiments. But I learnt a lot by taking on the universe. I didn't always succeed, though, but I was very happy making my conclusions.
There is no single phase for a screw-up. If you decide to being comfortable as a screwball, then that "phase" will always be hanging over your head. Even during the best of dasas and gocharas, the screwball doesn't see the opportunities provided by the loving unvierse right in front of his nose; he fails to see it because his sights are on some lesser things, he then loses the privilege of taking on that opportunity, and one day asks why he didn't receive such good "luck" like others do. However, there are "windows" of vulnerability in every personal period just as there are windows of empowerment and alertness in every dark phase. The Yin-Yang philosophy of balance affirms this very well. So, astrology revelas the cycles, yes, but you are the one who needs to learn how to manage yourself during those cycles, in its different challenging terrains.
Which is why I tell everyone not just to go to astrologers. The best way to get the best out of astrology is to learn astrology and apply it as a progressive and open experiment observing how you fit into your stellar journeys and how the stars fit in lighting your path.
Back to technicalities; astrology is about latent yogas surfacing through different timeframes. Use the vimshottari dasa system to determine the personal cycles and do the tracking of the gocharas against the blueprint of your chart. See how events relate to the triggering of variables in your chart, and conversely, anticipate events to surface when you see gocharas coming in to strike some parts of your horoscope. I strongly suggest you move away from the dasa for a while, and re-habituate your gochara tracking. You will
never regret taking on this recommendation.