there has been recent discussion about reducing VISA EXEMPT entry for people travelling from China to 30 days but there is no change in the gazetted law as yet.
ahhhh ok. Then if you want a hassle free way of re-entering the country I strongly suggest use land as much less hassles. Why not give my suggestion a quick message and they will say its ok or not and give you a price. I think you will pay ฿4000too.