If you don´t work with an if-construction in your lod-action you will get no
problems for a long time. As Tobias Runde told me you should use a scripting
like:

action house
{
while(1)
{my.z = (my.distance_to_the_camera > something) * something_else}
}

Instead of using "if(my.distance_to_the_camera > something)"
it works with simple multiplikation and makes the code very fast.
But there´s no need for scanning the distance anyway.
Just work with the x- and y-values and a multiplication.
If both distances are to big the value becomes 1 otherwise 0.

Using that way you can handle a few thousends of houses without any problem.
I made a mistake in my script and it created more and more entities using an action like this.
The only problem I´ve got was: "To many entities(50000)".

If you want to know a little more, look for "manual-culling works" in user-constributions or wait for my tutorial.

cu
Lutz