Hi learn2trade
My data subscription is not yet active, so don't use any software for now - I temporarily draw trendlines online, and calculate approximate levels based on judgment. It works well for me for the most part.
The thesis I work with is that you can draw fibonacci levels within multiple frames, and use 50% as the most relevant figure. I should caution that I am a novice with this, so a little knowledge is a dangerous thing. What I do is very rough, but gives me some levels to work with, and then I can watch the market and superimpose my own judgment of market action close to these levels.
I looked at Nifty, and saw the drop from 5228 to 3817; once it started recovering, I targeted a 50% retracement - which yields 3817 + [(5228 - 3817) * 50%] = 4522 - this was achieved, but Nifty could not sustain above this level. Once the move down began, I would expect 50% of the upmove from 3817 to 4522 to be given up - this yields a target of 4522 - [(4522 - 3817) * 50%] = 4170. I would extend this target if Nifty doesn't recover from 4170, the target being 75% retracement, which would give 4522 - [(4522 - 3817) * 75%] = 3993.
I don't want to be caught short in case of a sharp bounce back up from 4170, even if it turns out to be false post-facto, so would rather close out shorts by 4170. Using 61% would give 4092, which is close to your 4100 level.
Tell me if I am doing something wrong.