The data files for Omnisphere are stored in your STEAM folder. When you update your patches or soundsources, you are updating files in your STEAM folder, which was created when you originally installed Omnisphere. Your STEAM folder is located inside your Spectrasonics folder. See the instructions below to find your Spectrasonics folder. Inside your Spectrasonics folder you'll find STEAM, which may be the STEAM folder, or it may be an alias (Mac) or Shortcut (Window) to the STEAM folder.
On Mac, the Spectrasonics folder is located here:
Macintosh HD/Users/<Your Username>/Library/Application Support/Spectrasonics
From Mac OS X 10.7 and higher, Apple have made the User - Library folder a hidden folder by default. This is to stop general Mac users fiddling with settings, however, music makers will require using this folder from time to time.