I have been using this service for 2-3 years, practically since they introduced a better online system.
Unfortunately, I'm one of the many who, mysteriously, have never had it work and the IO employees don't understand where is the bug.
Important Note: CW (don't know the other IO) only accept EMS of Thailand Post, don't accept Kerry, Flash and other shipping operators. (This is what the employees told me)
Obviously, before sending the old original 90-days report, I recommend printing a copy, as you will receive back the new one no sooner than 20-25 days.