" I came from one scenario where the A person is having 4 small business. and his net income from each small business is 2.5 lacs, Now if he can file separate ITR against each firm name there will no Tax for him (Tax bracket is 2.5 lacs). If he file under personal tax there will tax on 10 lacs. income. which sounds correct since the each business has different capital investment. Please correct if my understanding is wrong."
Yes, interpretation is wrong.
Either same person doing 4 different businesses with four PANs !!!!!!1 (may be of his relatives)
Or may all not be propretorships.
One pan, any number of business or other taxable activities, all income is clubbed together for taxability.