That’s how LODs work everywhere - the distance is measured from the origin / centre of gravity of a mesh.
Unless you set position prop in Detailed - yup.
The way you’re doing it - ie. setting position of Detailed to actual position, then subtract the offset by setting the negative of that value in <points position /> would be the correct way. Alternatively, subtract that offset directly during points’ calculations - since it shouldn’t have been there in the first place 