@Rudolph ******
Each time you enter Thailand Visa EXEMPT you can get One 30 day extension of stay ADDED to the ending date of your stamped Entry.
In the Future, if you are planning to stay 8 months, I suggest you get the METV multiple entry tourist visa in your home country before you fly to Thailand. With it you can get up to 9 months stay with a couple simple land or air border bounce entries. That way, no worry about being questioned by Thai Immigration Officers upon arrival into Thailand Visa EXEMPT several times.