That's not actually true, I had this issue when I used them last time I played. Turn 1 from the 12" deployment I cast it 18" into his lines and hit him for 3 MW. Next turn he won but elected to go 2nd, sent it back 8" my way which was well within the 6" as I had moved up 6" to shoot at him. (18 - 8 - 6 = 4"). Next turn I won but had to take first turn to try and reduce the amount of units in my face and retreat a bit, he moved it 8" deep into my territory.
It's great fun to play, but just be aware despite being one of the longer casting spells it's still quite easy to get it turned around and thrown back into your face. I hate to think what would happen with the 6" casting range of some of the spells.