Economies of Scale

This is where the rating stops being a score and becomes money: the interest rate you pay per tick on any loan, at your current rating and one level either side.

Each factor is worth the same. A factor you have nothing to be judged on — no loans, no upkeep on record, too little history — scores half marks, not full and not zero. That is why a brand-new company sits in the middle rather than at either extreme.