Is it permissible to deduct a portion of a quotation amount for additional effort outside the scope of official work and for which no payment is received from the company?

It is not permissible to deduct money for work outside the scope of the agreement if the employee is able to refuse it. However, if he is compelled to do it and is exposed to unbearable harm, then there is a difference of opinion among scholars regarding the permissibility of deduction. This issue is known as "al-Dhafr" (seizing one's right).