I just did my first 90 day report in Ubon Ratchathani and I was completed in 5 minutes. I handed my completed TM47 and passport to first desk, they told me to go to the next officers desk. They checked passport and stamped a receipt for 90 days. There was NO CHARGE for this. I took a heap of documents with me but didn’t require anything else.
Ubon Ratchathani Immigration is the best. They made this very simple.