Normally these amount is seemed their income by Revenue Bureau of Thailand. ISTH has to pay this tax for this amount. This is called “Tax on tax” and it’s normal treatment. By the way, this amount is included penalty? Because I heard from DENSO, if tax payment is delay, we have to pay some penalty.
(Important)
The company, ISTH will start the deduction for Japanese from next year. So their total payment will be base salary + income tax. And income tax will deduct from total salary so that they are going to receive just only base salary. Do you understand?