Hello
When Mbox Split feature was not implemented, I wrote a code and comparing it with your new 24.6 split method, yours seems to be about 10 times slower!
May I share my code so you kindly pass it to the devs. might …... Until version 24.2 it was OK, but version 24.3...check what happened between 24.2 and 24.3. An important symptom...