[Lorenzo Andalò]

Yes, you are right, the SRS app was made before SteamVR implementation for the main game, so now you can launch the game from Steam just using SteamVR, but the app still launch it in the old way, so you still need the launch parameter line for VR in the SRS profile... regarding the resolution, before SteamVR update, if u didn't insert any number, the default one was loaded (1.4?), so I guess that now, after the update, since the resolution is normally decided by SteamVR, you always need to insert the value you desire...
In the end yes, the issue is the app outdated regarding the VR option implemented by the main game, we'll need to do things the "old school" way untill the app receives a massive update (and I'm not a programmer, but that sounds like a lot of work to me)