it's been like that (the SI) for a long time now (must be 3 years or so), everything is still there, coming from the old tech dosc, things initially were a little harder to find, but once you get used to it, it's pretty easy for most items, + there is a lot more there (EV, DM, UM & SI) than there used to be on the tech docs, from memory, the tech docs only had the EV & UM, not the SI or DM.

For why the change, guessing the old tech docs was just that, old, and didn't provide all the info that the current system does.