In my country, the foreign exchange rate risk that includes losses due to currency conversion via local funds transfer can be deducted from the gross sales (derived from receipts/transaction history report) together with Upwork fees and the local funds transfer rate. This is new information for me actually but it looks like your service tax is equivalent to our monthly percentage tax which is 3% of the taxable amount a.k.a. net earnings per month. And then we have a 40% optional standard deduction (OSD) which is applied to net earnings only. The 40% OSD is for all returns. I am not sure if the FOREX rate risk can also be applied to the monthly percentage tax. The information that I got is that it qualifies for all INCOME tax returns - quarterly and annual ITRs. I am not sure if this information can be of help to you. But this is my best attempt. I am still learning, Priyanka.