1script - 10:43 pm on Sep 26, 2012 (gmt 0)
I never heard of minus 900+ penalties mentioned in relation to Panda. Usually its effects seem to be less drastic (position-wise, not traffic-wise, -50 would already be dead enough) and much less specific - you'll be fluctuating between some low SERPs but not all the way back to 900+. And it would be really hard to give it a particular "minus xx" number - yours seems different.
reason for a minus 950 by Panda
Are you sure your issues are Panda-related at all, have you checked the -950 timing against the Panda refresh schedule posted here at WebmasterWorld?