Because there seems to be a problem with bracketing in the XML, and the results are sometimes weird. And quite a few times I got incomplete XMLs because the session in panoshoot froze or got disconnected while shooting
Basically there are two options triggering the camera and storing the information in the XML:
1) one pulse triggers all bracketed shots as a series, one impuls per position is written in the XML. This is ideal for those who process the brackets BEFORE stitching.
2) each bracket ist triggered seperately and for each position the pulses get written in the XML seperately. Thisi is ideal for those who import the brackets into
APG and hget them stitched as stacks.
The panoneed head for example allows both ways - you can select to connect the camera to the controller (one pulse per position writte to the XML) or you choose to connect the camera straight to the head and get the number of exposures per position written into the XML.
This way you have all options using PromoteControl and other devices or hacks like MagicLantern in a very easy way.
P.S.: 9 bytes is a usual size for the XML file from a 6 - 7 shots with a fisheye.