Extrapolating the cost of jump engines in the shipbreakers manual I would estimate the cost of just the engine to at least 640mcr, being class V seems to be another 500mcr or so. Perhaps the low battle score does warrant more of a discount than I was thinking. I went with 1bcr for the J2C-IV jumpliner in my submission due to its massive cryopod capacity, but perhaps I went a little overboard. My thinking was that there would not be much point in building the regular ships if you for just a little more could construct a ship with vastly superior capabilities.
Also I just noticed that the Mnemosyne is missing hardpoints and upgrade capacity. I am guessing no hard points? but no upgrade capacity seems like an oversight.