Maybe the monitor volumes are too loud? I heard for studio monitors like the 305's it's best to keep them at max volume, which is what I do.
I wouldn't do that, especially if it's forcing you to run the Kemper output so incredibly low.
If I was in an apartment I wouldn't have anything at max volume. I think it would only best to have them at max volume when you're in a place where volume isn't an issue and you're running a signal at a normal level into it. In other words, you aren't getting any benefit by running them at full volume when you're just running the Kemper output at a tiny 0.1 or 0.2.