Sure, most of monthly income based retirement extension are based upon pension. The reason is simple, because most people in the world that choose to retire do it at the age of pension and do receive such funds. I know it is different depending on what country you are coming from, and also what Immigration office you are using in Thailand.
However, down to the core, as far as I know, there is nothing standing in the immigration law that states more than you might have to show origin of funds regarding country and possible bank account. No where does it stand you have to show who transferred the money to your bank account. That, because the origin of funds, will always be your bank account in another country if you are not sending your pension directly to your bank account.
Just as a small note: What they love or like, has never had anything to do with it.