When calculating large values with computers one is using Floating points, when calculating distances this can be a problem.
The floating point problem:
Eg. In early Kerbal Space Program the kerbins would hover above the ground 2-3 inches because of the floating point problem, this could be fixed either by calculating the distance from the nearest body or by upgrading to a 64 bit system.
Now in this world (made by a company, very happy for their trademark), the AI computers are really "zombified human brains" and it has access to large ships that can travel vast distances, by shifting in to another plane. Calculated and partially controlled by those brains or spirits, along with ancient holy computers.
Now, how big is the bit rate of the brain (after it has been clenched of personality) used purely for calculations and instructions, how "off" can one expect to be if by comparison kerbol's diameter gives a few inches inaccuracy, and those ships travels between suns.