I heard this for the first time yesterday at a management briefing on the east side of the Atlantic. It seems cover isn't dynamic enough on its own.
Google seems to indicate it's only a year or two old.
I agree with @Daniel that the Microsoft example is probably using 'cover off' to mean unveil (as in 'take the cover off') because the context is reserving 'cover off' for the new stuff. But this would certainly be a novel use of 'Cover Off' in BrE at least.
My guess is that techies started using 'Cover Off' as a shorthand for 'take the cover off' in some technical contexts and then as a metaphor for unveil. Management types misheard this as a novel and thrusting way of saying 'cover' and ran with it.
It's particularly prevalent in MSDN blogs in both senses.
Googling "Cover Off" with Sharepoint yields what looks to me like a significant no. of hits in the 'cover' sense. I am tempted to call it microspeak/sharpoint.