Nice observation from the pic, AC.
Interestingly, I have found a VERY similar situation exactly 1 year before in the last december 2010 timeframe.... Please check the following image for dec2010, where 2 stochs are together and still market going down(very much like current situation after some 500 points down and then little recovery and then again starts going down etc...)....
So based on the above image, it looks like a similar current situation happened before also and point is, even last year before making any big movement(the jan2010 crash) both the stochs diverted & joined again to do so....
If you want to know about the small intermediate movements also (like the current down move), use (15,3,1) along with 2 others in the image. That gives some more idea .....
For question regarding, how to take trade, i ll update in my next post...
Thanks,
...summasumma