I can't say that I have seen my phone stick at 100% like yours either. It has adjusted though, where I see it at say 20%, and shortly after being in a dock, it jumps to 40% or so.

As for the battery drain issues, I've noticed it can vary depending on what app you leave open when turning off the screen. If I leave Google Maps open for example, the GPS still seems to remain on and tracking. If I leave the camera open, it seems to keep the sensor active, along with the GPS. Both scenarios lead to pretty rapid battery drain, and an indicator in the usage panel that the phone was not fully in standby mode.