I'd think that the clouds would fill the shadows a bit, making the total subject brightness range less. If you base your exposure on the shadows, then scenario 1, complete blue sky, would likely be more exposure and less development. The same scene with lots of white clouds filling in the shadows would be less exposure but likely a bit more development. I think I end up with N-1 in the first case a lot more than in the second, especially if I'm using any blue-subtracting filters.

Best,

Doremus