I agree that Discovery is harder than most mods, So comparing doesnt work (Trust me, I've been around 10 different mods and so far, Discovery is the best I've seen. Great challenge, good trade runs (Not too much profit, but great profits with many places for pirates to hide.), Great ships, Very Balanced.)
Over all, you also have to understand that Battleships arent cheap, and I think 450 mil (On average) is a little too low. (Especially for the Rheinland BS, I think maybe the price of the Rheinland BS should be a little higher than an average BS because of Rheinland's Economical delema at the moment. Just throwing a suggestion to help RP..) Also, the sheer number of supplies and equipment, crew, and time that goes into a BS, it doesnt appear over-night. These factors are what contributes to a BS's high cost.
I agree with Korrd in how the BS should be more expensive. Should be left to those with big pocket-books, or to the factions. (Then again, People are flying more and more Battleships and I noticed that a few were missing appendages...:rolleyes:)