2 hour is plenty of time.if you fly the same airline you can even ask to label your bagage to surathani .on arrival just follow the signs for domestic connecting flights ,it might not show surrathani ,but it is your gateway to your next flight .it is about 200 meter after the normal pasport control,still before pasport control .safe journey
Tm 7 and tm 8 only from samui immigration .nr 11 and 13 can be done at service office next door .photo's also inside house ,as a precaution .can also be printed at service office