[vidarh]

If you care primarily about the financial impact of jail, then that would be an argument for the opposite of what you suggest: A rich person is likely to be less affected by the loss of a days income than a poor person, and so if the financial value of the time spent in jail was all that mattered then rich people ought to be imprisoned longer for the same crime, not shorter.

Since the financial impact is not the main consideration of jail time, it shouldn't be major factor.

With respect to children, children whose parents are imprisoned are more at risk of future problems, and so irrespective of other considerations it may well be preferable to society to take it into account.