What is the ruling on changing invoice numbers for customs and the value of the invoice, and what is the ruling on calculating interest at the behest of the company owner?

If the profits are usurious, it is not permissible to work on calculating them, due to the assistance this entails in committing something unlawful. However, if they are profits for a company that operates in permissible activities, there is no objection to calculating them. But if the company operates in unlawful activities, it is not permissible to calculate its profits, due to the assistance this entails in committing something unlawful.