delericho
Legend
And if the manual only accounts for standing orders 1-50, well, it's not like the Jedi have a decompiler to search the source code...
I'm inclined to go with the alternative explanation - that Order 66 is one out of thousands of standing orders, and so easy to miss. Indeed, one of the SWSE books says that Order #65 is actually a kill order on the Chancellor, stated in exactly the same terms as #66.
So I'm not too bothered by that in isolation. But put it together with the questionable origins of the army, and I find it much harder to swallow.