Mota Collapse - Is There a Difference in the Effect?

In the argument from divinefom for mota collapse, a god created this world, right? His actual effect is this world, with everything that exists. But suppose that he could have created another world, or no world at all. In that case, this possible difference in effect would require a possible difference in the cause. So i think that the motal collapse argument assumes this principle. I think that the proponent of divine simplicity, who wishes to avoid motal collapse, must reject this principle.