Yes, we do the same. Everyone has to be 100% comfortable and satisfied with the way a song sounds before we play it live. And because none of us are professional musicians, it means a lot of time has been put in at practice to getting it sounding good. Once the song is ready to play live, I think that experience is much more valuable than any practice time alone at home. So that's why I don't practice scales and technique, I practice songs. It's one thing to flawlessly play something in your bedroom, it's another to play it well in front of an audience with a full band.
At practice on Friday, we spent the entire 4 hours on one song, but that was starting from ground zero to a finished song. While we were warming up, the guitarist came up with a cool riff and the drummer put a cool beat on it and that's how it started. We worked out the intro, verse, chorus, solo, and most of the lyrics. The singer is working on the lyrics more this weekend and we'll change some small things in the chorus, but the song is 85% complete. That 4 hours of creating with three other people was more valuable to me than practicing 20 hours at home alone doing scales and exercises. I play bass because it's fun to create and play songs with others and then play those songs live. If I'm not doing that with my bass, then I feel like it's a waste of time for me.