Itr 4 for sales commission agent

For a sales commission agent of beauty products who gets a commission of 5%, last years total commission was 75000. No accounts maintained- the nature of business is that after the sales has been made between the beauty products company and salon, and when the salon makes the payment to the company, I am paid a commission of 5% of the total payment made by the salon. That commission is paid to m after deduction of TDS. My Questions are-

1) I will be using ITR 4 for filing returns- correct?

2) Gross receipts that I will file will be 75000 and not 75000*20. Is that correct?

3) No sundry debtors, creditors, or stock accumulated - as that is maintained by salon

4) Can I can file an expense of Rs 5000- for the year which is my travel and mobile phone expense?

Thanks in advance for your advice and answers.