Don't kid yourself. This is 100% calculated at the top. By waiting this long to give any notice after the first announcement the suits are trying to lull everyone into a sense of calm and relief. But it's only temporary.
The reason is simple. sending out notices quickly after that first announcement would have raised a huge stink, and would have caught the attention of the wide-spread press. But making that announcement and then moving slowly – a few cuts here, some VPs gone there – over four or five weeks means that each round doesn't seem quite as bad as it is.
Think about it ... hearing about 4,000 layoffs in one month is horrible. Hearing about 20,000 in a month is disastrous. Also, learning about layoffs in group A means the people in groups B-D start thinking maybe they're safe.
My guess is the next genuine cut will come on 6/30, followed by another on 7/14, and then another on 7/31. But none of them really massive. Keeping it to 3,000 - 5,000 at a time and restricted to certain business units just makes it a little easier to handle.