Nope, you don't get any info on this, sadly.^^ Only thing you get info on is Spire telling you in the Imperial campaign that you can only send in as many ships as your command limit allows. Not at any point does the game tell you that warping out ships does not only save them from destruction (well...most of the time, sometimes they get eaten by daemons whose realm the warp is), but will also let you receive the remaining ships of the fleets you send into this battle. I actually had quite a few battles by now where I had to warp out a good amount of ships...and I lost at least one to daemons eating the crew. xD