Mine was slightly longer, 30 minutes door to door.
For all of you who use the Surin Immigration Center, if you arrive there at 08.20 you have the pick of the parking slots. The roads are empty. Park the car, go into the building, up the elevator to the third floor, and you will probably find yourself in pole position on the starting lineup. I did. As I was signing in, an IO approached me, said good morning, and asked what I was there for. I said 90-day report. I handed him my passport and he started the process while I was still signing the register. Great service!