That's not how it works. There's no authority over the production of the shilling - anyone can make them, and they therefore trade at the cost of production.
Which means that regardless of the number you print on the notes, if buying something took a brick of them at the old denomination, it will take a brick of them at the new one too.
Which means that regardless of the number you print on the notes, if buying something took a brick of them at the old denomination, it will take a brick of them at the new one too.