Well, there is a little bit of confusion regarding the money. I'll try to recap it.
First of all, all of us had 62.000 gold royals to buy magic items and such. Any money left after the purchase of magic and mundane item is converted into silver pennies: 25 for each gold royal. The reason of this strange conversion (normally it's 100sp for 1gr) is that the initial amount of gold was intended to give us magic (and exceptionally rare in this world) items.
Therefore, we have two money transfers. First, they give us 2500 gp and then they require 30.000 gp for the patent, although we only have to give 5000 as the others can be loaned.
Now, JA forgot about the monetary conversion, so either he meant those sums in golden royals or in silver pennies.
1) He meant it in golden royals. Each of you has to provide 2500 gr, aka 250.000 silver pennies, aka 10000 of gp left after the initial purchase of items. That is a really huge sum, so I don't think this is the case. So we have option 2)
2) He meant it in silver pennies. Thus, you have to pay 2500 silver pennies, aka 100 gp left after the initial purchase. This is not very much, but if you have more money, you can spent the full 30000 silver pennies (1200 gp converted), in order to avoid the payment of interest.
Some of you may have left a lot of golden pieces (like me), and now, multiplying by 25, they sit on a mountain of silver coins. The reason is easily explained: we were chosen not only because of our skills and reputations: they knew that we are rich and they thought that it would be better for the colony if we were interested and invested in its success.