Yeah, that's what I thought at first - it's quite possible, but I think there's a very slight variation in the name. I think the one in Huan Hua Xi Jian is something like..."Wu Xing Mo Gong" (Five Elements). I guess you could also argue that with time passing, the names and titles can change because the later generations became more afraid and in awe of the Wu Xing Mo Gong so with added respect, they call it Wu Da Mo Gong.