This is one controversial baby. I want to discuss it more and see if we can reach any new conclusions.
One strange thing, if this information is correct, is that no one who witnessed a LDA ever thought "wow, the range of the attack is beyond my capability." Even much weaker bystanders never thought this. And yet, even for a tiny detail when Xiao Yuanshan used a freaking WHIP, Jin Yong made Xiao Feng think that "I could not do what [my father] did." So why no one ever thought they were incapable of LDA in DGSD or SPW? I know that Yin Tianzheng gasped when he thought of the possibility of Song Yuanqiao being capable of LDA, but in DGSD or SPW no one seems to be surprised or impressed by the ranges.