I don't own one now but I've had two 45SP's in the past. There are non-Wista brands of lens boards made for the cameras that have the hole centered. I've used both and never found any real difference in practical use.
I think it's to allow more rise or drop of the front standard. More drop used as is and more rise by putting the board in upside down. At least thats what I can do with mine. Maybe the way the Tecknika was put together held the board off center so the hole was offset to accomodate that. Just a guess.
By putting the hole below the center line of the lens board, they get front "fall" for free. If I thought about it long enough, I think I could convince myself that this allows a more compact camera design.
When the lens is below center on a Linhof board, the lens should actually be centered on a Linhof camera, so you get more front rise potentially. With large lenses, the lenses are usually centered in the light trap, though, so they are above center for Linhof, but they usually have enough coverage that it doesn't matter.