1. Hope you have taken into account that there will be a TDS (tax deduction at source) of 20% at the customer end when they pay this amount. The service Invoice also cannot be paid in advance and can be paid only after the service is completed. These are as per govt rules.
2. I also suggest again that AGR Bangkok applies for an Indian PAN(permanent account number). TDS then becomes only 10% and this amount can be claimed back too. I will send you the documents that you need to fill in and return. We will apply for the PAN in India on your behalf. Please confirm this is OK.