I think the most useful way to track DMI in regards to training is to compare only those values when GS is at 9. In the absence of training or stamina drops, DMI at 9 GS is the same.
Is that really true about 9GS? So if a player with 9GS has his DMI increase by 200, there had to be a very small amount of training?
I've had a few players that were at 9GS for multiple weeks have their DMI go up & down very slightly. (Talking about couple hundred point swings only though). So that would mean it had to be something like this: 1 minute of training by accident (increase), then a slight stamina drop (decrease), then another 30 seconds of training by accident (increase)?