Office365 Current Channel installer doesn't update but installs whole office 365 suite?... also where is the data stream stored while doing updates?

we have deployed office 365 (some pc's have full suite) others have selected apps only... and what we discovered if user has just one 365 app the installer installs every app of 365... it doesn't actually just update existing components.. Other thing is we manage repository locally and use group policy settings to set version and deadlines for upgrades and the source is stored locally on our servers so each asset doesn't make outbound connection and download 2 GB of data. Where does DC store the stream files when it does updates for 300+ pc's... are or will there be custom settings to use local repository instead pulling data from Microsoft on every update? Can someone elaborate how the whole update process for 365 runs?