Damage is random in ships and bases, in satellite stacks, and in WPs on planets. It used to be you put components into your ship 'left to right' and they were destroyed 'right to left' in SE II, NOT III or IV at any time!
In the earlier Version of IV you did indeed see WP stacks and satellite stacks destroyed in a certain order. That has been changed. There is a tendency for smaller units to be destroyed first but even that is not absolutely predictable.