Is it permissible for a sales representative to manipulate invoices to cover the number required by the company, such as giving the customer a lower discount and dividing the invoice among several other customers, to avoid bearing discount differences?

The questioner's unease is justified. The company's representative is a private employee and an agent, and his hand is one of trust. Therefore, he is not permitted to act except within the limits of the company's authorization. The method mentioned for manipulating the number of invoices is impermissible because it combines wasting the customer's right to a discount, violating the company's regulations, and breaching the trust of the work.