No, no magic computer for that as far as I know, which is admittedly limited. Yet another reason the AS limitation (which apparently is going away in some places in the US??) isn't held that tightly.
The bigger issue would be a huge wind, where some guys are showing 315 one direction where others are showing 185 the other. If you are the dude showing 250 where all your same way-same day guys are showing 185, I don't think it would take a rocket surgeon to see what is going on.
As for the 5% thing... Yeah, why don't they just get rid of that "rule?" Has anyone actaully payed any attention to that? I know in T45 land it wasn't even mentioned, and we were ALWAYS at least that far off what we filed for. I can't imagine it was any different in the big jets.
