Normal… i was submitted on April 20th and just got an email asking for more documents now.. also i nthe embassy website says it takes up to 10 working days for visa processing time…
I called the immigration in Chiang mai and they said if your current visa is still valid. You do need to cancel before applying for new visa. Unless your visa is already expired on Oct 18th? If yes, then you no need to cancel as its already expired anyway.