Commission Income is not a Business Income
Case:1 Commission business can not be offered for Presumptive Income u/s.44AD. As per Section 44AD, you have to offer Minimum of Rs.3,76,000 ( 47,00,000x8%) under the head P.G.B.P and offer Commission Income (net of Sub-commissions) under the head Income from other sources(assume it is not one of your principle businesses) and in this case as you dont have any other Business Income having turnover exceeding One Crore, not liablie to tax audit under section 44AB
Case:2 Since as per your assertion, Income from your business(even considering net Commission) does not exceed Rs.1,00,000, you can offer such business Income as Normal business and Commission under the head Income from other sources(assume it is not one of your principle businesses). As you offer Business Income less than 44AD (<8%) and your Income(Total) does not exceed Maximum amount not chargable to Tax, No liability to carry out tax audit u/s.44AB
Commission Income is also Business Income
Case:1 Since Commission Income can not be offered under Presumptive Income under section 44AD, You can offer Railway contract Income under 44AD and Commission Income net of Commission expenditure as Normal Income under the head PGBP. No liability of tax audit u/s.44AB
Case:2 Offer Rs.1,00,000 as Business head income. As Tax liability does not arise, not liable for tax audit u/s.44AB
In all cases Maintenance of books under Section 44AA is Manadatory as Turnover under all cases exceed Rs. Ten Lakhs and 44AB Tax audit is not necessary in all cases