Ooh, I appreciate the diligence! The numbers here came from manually fiddling with more granular output from Pavgran's special purpose "profiler" script. One of those steps, where the DBCA assumes control of the bit stream, takes 1615 gliders. I would bet I made a mistake and added it twice, probably to both the DBCA building and the task of the DBCA itself. It belongs in only one of them!
I can verify this later.