The Management Fees figures come from transactions directly, not from the Statistics table.
When you close off October, the very next set of transactions are assumed to be part of the new month - November.
But they closed if you close off November using the Date of the 2nd December transactions look like they belong to the month after the close off date - January !
Then say, December closes on the 2nd January, so all of January transactions after the close off are assumed to belong to February!
Then in January it closes correctly on 31st January, so all of the February transactions after the close off are again correctly assumed to belong to February.
So February will end up with 2 months data.