> the swan mark would have to be purchased at the price of six shillings - swans not included. This was about the same amount as a year’s wages for a household servant.
One pound would be over three years wages for a household servant.
> You're asking why they didn't round to the nearest £722.74
No, the question is dumber than that. The proposed "rounded" fine is well over double the original fine; rounding to the nearest four pounds would result in a fine of zero.
> the swan mark would have to be purchased at the price of six shillings - swans not included. This was about the same amount as a year’s wages for a household servant.
One pound would be over three years wages for a household servant.