Can someone help me in finding, of why this happends:

(1) when i copy any key of animated object from the timeline and paste it anywhere in the timeline of that same animated object, all the keys moves one frame forward as if like I had given them a breakdown, but breakdown was never used.Why this? I want my keys not to move from their place.

(2) The other problem is completly diffrent from the above one.
If I adds any blend shape to an object for facial animation and when I do delete by type history to the blend shape of that same object, the blend shape gets deleted. The problem is, after adding blend shape to an object, I need to do some adjustment by which by which object's history increases. I want to clear my object's history without deleting blend shape history. Please help this out.