Filling itr for form 16 & form 16a simultaneously

You should file Form 1 as the commission income you can show as Income from Other Sources as it was casual income for part of the Year and the salary income you can show under Head Salaries]

You have to file ITR -4 in which there is income from salary and income from profession.  In ITR - 1, income from business or profession would not come.  Your earlier income is income from profession.  Hence, file ITR - 4 where you can show both your income from profession and income from salary.

Work out your income tax computation and TDS amounts as per  Form 16 and Form 16 A.  And can claim refund or pay income tax accordingly.

Simply you have to file ITR 4. Anyways u can select the option as Regular books not maintained thereby simply input the income and expenses in P&L section at the below at around 50th Line item and cash balance if any in B/s Section.

you can not file two forms for the samle AY .