there is PID and there is "PID" applying this to a software system is a little bit easier as because you don't have the limitations of a physical systems (the

there is PID and there is "PID" applying this to a software system is a little bit easier as because you don't have the limitations of a physical systems (the performance of the system are highly dependent on the transducers and the execution units used in the system) there are control algorithms that tune the PID parameters on the fly (google "pid autotuning"). All but the most trivial PID controllers have a certain form for autotuning nowadays (even for physical system as you've pointed out the parameters of the test system do not match the actual systems 100% and also the parameters drift in time due to wear and tear).