It doesn't have to cause a disruption of the entire proc-gen system if it's done as an post-processing sanity check. That is, calculate everything normally first, and then make adjustments. This is all that's happening in a single-system override anyway, but the same thing can be done widely too, if they had the desire to do so, but that runs afoul of the ridiculous amount of possible edge cases and conflicts that we were alluding to earlier, which I think is the main reason they would avoid doing a global post-processing adjustment.