Vegeta922002

Not to insult your intelligence, because the formula is exponential in nature it can be vastly cheaper to purchase ships in steps. Ie buying a basic cargo hull, moving it the maximum distance the following turn and then upgrading it to a constructor. This will save you a few hundred credits because you are stopping the power of compound interest part of the way through. I have been able to save 15000 bc on purchasing capital ships (playing all research/economy)

For shipyard rush buys you are charged for the cost of the remaining production to finish the project. You see different prices because there is already production made towards the shipyard when you made the purchase. This happens without the user noticing due to one of two dominate factors - you are using a planet you conquered but had not yet built anything in the shipyard (the enemies production carries over to your project) or you used the governor to stop building all ships o