Is it true that you cant use collision on physics objects set at "complex as simple"?

HI everyone.

I just wanna make sure on one issue.
Looks like you cant use collision set as “complex as simple” (flush with mesh) on meshes you have physics enabled?
If I try other “looser fitting” collisions it works fine but “complex as simple” gives me an error.
Is this correct?
Thank you for your kind answers.