The algorithms that are used by companies that sell credit reports are proprietary intellectual property that they must protect against copying.
Thus, their inner workings are not publicly disclosed, and are strenuously protected by the vendors as trade secret information.
That is the primary reason why simulators, even if produced by the company who vends the scoring algorithm, are intentionally broad in permitting simulations. Very precise simulators that would permit simulation and scoring of very specific changes/events would permit others to reverse engineer the algorithms. Since the vendors chose not to secure patent protection, but rather rely upon trade secret law, reverse engineering, if successful, would then allow them to make, use, or sell the algorithm.
