I believe the amnesty works only for people on tourist visas, or visa exemption stamps. I'm in the same boat as you, but I'm on the ED Visa which expires on the 21st. From my understanding, we still need to go to immigrations and apply for the emergency extension with the letter from your embassy.
I told my embassy that I was on a 1 year ED visa, which is expiring soon and they have issued me a letter. Are you sure its only for tourist visas/exemption stamps?