[Mobhack]

As I said - you have to wait 1 turn so your off-map arty is available for use before plotting in non assaults.

You can still plot your arty gold spots where you want the DZ(s), if you don't want to wait 12 odds turns, in turn 0 of other battle types.

When arty is available to plot , then so is your air landing force.

cheers
Andy