Do you think that this tower can be some kind of obstacle for him? To find out if it's possible I took his place in this tower as a player but imo everything should be fine.
Possible, I noticed the AI wont fire over sandbags if they belong to the same side. So the thing your firing from, could effect the AI, even when it looks ok from the players point of view. Plus if your Sniper is jumping down, he is probably looking for a clear line of sight? And out in the open his firest reaction is to go prone.
I can hardly believe that it's possible but haven't tried it out yet. And besides my mission is on Kolgujev island where there's almost no flat grounds there - at least in my mission's area.
High ground is definetly an advantage
But I had a mess around and the Reveal command works great, better than DoWatch with standard units. So it probably is the tower or something else. He will open up around 900 meters on Kolgulev. here's my test mission:
900 Meter SniperIt's worth viewing just from the Targets point of view, not often in OFP you here the bullet fly past before the shot.