Night Visibility

[Ashcloud]

This is normally 1. I am just finishing off a Korea scen, Kap'yong April 1951. This is over two nights and one day, 55 turns, Visibility set at 8, Night scenario box ticked. THe N/D/N transitions will be done manually.*
The scen starts at night. On opening the Scen Editor, the night aspect appears, but the visiblity is 2, rather than the 1 that it should be. If I set the vis to 0, the correct night vis of 1 appears,but this would surely mean the day vis will be 0.
Any thoughts?
*Using Huib's method, instructions provided. This should be irrelevant to the problem above.

Full moon.