Curious to see if the 2nd phase applies more to countries they operate in that don't have "at will employment" style legislation, it might go some way to explaining the two phases. That would fit into your point b).

IIRC, the first set of layoffs largely affected the US a lot more than Europe - its a much more involved legal process generally to perform layoffs in cities like London vs their US offices and often can't be done as quickly.