thank you for the post, however from this web site it is not a clear yes on going through the immigration in Krabi.

If the final destination is Chiang Mai, Chiang Rai, Krabi, Phuket, Hat Yai or Samui, passengers have to proceed to Domestic Transfer Check-in Counters - East at concourse D, level 2 before proceed to immigration and security formality. Customs formality will be done at your destination airport.