Hardrock25 Wombat777, page-132

I agree with you, because this is where the best markup can be made for the Sri Lanka and Thai buyers.
I do however feel that the first three schedules would have also likely sold due to their naturally premium-higher quality. Always good demand for +10ct fine grade pieces!
As for the rest of stuff in between this is most likely where the poor grading or better manacle lot size and guidance could have been possibly improved.