From what I’ve heard from doctors, xr is equivalent two doses released into your body, its not a steady state release as you might expect. Its basically one ir and another ir wrapped in a package that takes a few hours for your body to digest. So if you don’t really have issues with timing and xr costs you more money then ir is totally equivalent and ok to use. If it feels different, then it might be manufacturing differences. To really determine the difference you would need to get it from the same manufacturer for both the xr and ir versions. Which doesn’t surprise me after listening to a podcast about a book called bottle of lies.