Is it permissible for a student on scholarship abroad to submit an invoice for a value higher than the airfare ticket subsidized by the state to obtain the due compensation, if the responsible employee disburses the lower value based on his own discretion and in violation of the agreed-upon laws?

It is not permissible for an employee to change laws unless he is authorized to do so and has the authority. If he is not authorized, there is no harm in changing the value of the invoice to obtain the agreed-upon right, even through deception, for someone who cannot access his right except by this means. However, if the employee is authorized to act and change the law, it is not permissible to deceive him and forge invoices to obtain undeserved compensation. The matter depends on the extent of the employee's authority.