IMO you have to play this a bit by ear when you roll up the mission boards etc. I usually play that they do since typically the delay on the S? is balanced by the delay in your ability to react, but delaying conditions can sometimes make a mission unwinnable for the S? (or for you when attacking for that matter.) Nice thing about solitaire play is you can always experiment with less extreme but still delaying parameters for weather effects. Alternatively you could adjust the VP's the ENEMY gets for EVP or other VP for the mission so it's a bit more balanced. In my experience the ENEMY rarely racks up much in the way of EVP even in perfect weather.