I have to say, I do like me a "story driven" scenario - certainly makes me care about my pixeltroopen a lot more!
Are these positions supposed to be prepared tank firing positions?
Not going to lie, they don't work all that well, and I think there is a better way to make what you must've been trying to accomplish:
Here's how it looks like in the editor:
Hold CTRL when you do a direct elevation set to create those "blue" markers - those produce a "Ditch Lock", a much steeper elevation change.
Normally you'd want a 2-meter high berm for a good hull-down tank trench, but since these are on a significant elevation to the expected enemy, a gentle down-slope away from the berm will allow the tanks to inch front and back to find the perfect hull-down position.