Rental, petrol etc are all tax deductible. These are expense to earn that income. Not sure why is taken as non-deductible. Anyway I think they are using the taxi income which is net and assume the same for Uber/Grab. The latter you take the gross income and apply the deduction as you prepare your returns.
I don't get it..all expenses of the car should be tax deductible as the car is the business...to not include tat for deductions is a joke...but Singkieland income tax soo low...argue also pointless...but should be no tax at all as already pay COE..ERP...fuel tax..gst etc..high running cost