You can count the value of the old coinage by weighing it, you really think that such a system was an accident? I mean, I'm familiar with the history so I know

You can count the value of the old coinage by weighing it, you really think that such a system was an accident? I mean, I'm familiar with the history so I know 12 of 20 was a deliberate choice, but if you don't want to read into it, ask yourself if that's plausible.