Nothing requires the charge to have LoS. The rules allow (by not disallowing) pre-measurement, but it is possible different groups have different default values for that.
I don't want a measuring guess to factor into the game, but also don't want someone to take a long time measuring everything.
I play AoF rather than AoF S, but there aren't many differences.
By the way, questions get answered pretty quickly on the forum.
http://onepagerules.proboards.comandy