I'm not sure I completely understand what you mean.
In the preferences there is an option "Automatically align images after loading".
When this option is ticked, then the images are completely aligned (with the assistant) after loading. The equivalent at the command line is here hugin_executor --assistant.
When this option is disabled, then the images are roughly distributed (depending on number of images and field of view). But this is done dumb without taking the image content into account. It just puts the first image left and the last one on the right (or when there are more images in several rows). But this is no estimation and no calculation. (From the command line something similar can be achieved with pto_var).
Thomas