After I cross check again. I found raw materials purchased from local (Exchange rate = 1.00 THB).
I will adjust exchange rate Those additives and base oil as below
2015 : Local item Exchange rate = 1.00 THB. I will adjust 1 USD = 32.60 THB (follow e-mail below)
2016 : Local item Exchange rate = 1.00 THB. I will adjust 1 USD = 35.48 THB (follow e-mail below)
Note : The raw materials are imported. I will use the actual exchange rate.