Thank you both for your very fast replies -- I think that I should be able to get it to work now, provided I don't run into any other issues. 
I do have another question though -- harpo, you said that there are a possibility of 9 upgrades with up to 9 levels each; would it be possible to make more than 1 tier of the same upgrade type? This is what I mean:
ex:
A starbase already has 9 different upgrade types, but you want another type. From what you said, the game has hardcode limits that would normally make this impossible. Would it be possible to do something like this to get around that limit:
upgrade 1/9 -- 4/9 levels
upgrade 2/9 -- 3/9 levels
upgrade 3/9 -- 2/9 levels
upgrade 4/9 -- 3/9 levels
upgrade 5/9 -- 1/9 levels
upgrade 6/9 -- 1/9 levels
upgrade 7/9 -- 1/9 levels
upgrade 8/9 -- 2/9 levels
upgrade 9/9 -- 2/9 levels
your custom added upgrade - upgrade 10/9 -- 3/9 levels
Instead of trying to find that hardcode limit and change it, could you just make some of the upgrades part of the same categories -- with earlier levels as their prereqs -- to make 'room' for another upgrade type?
ex:
Combine upgrades 1, 2, and 3, because 4+3+2 = 9, which then means that there are actually only 7 different unique upgrades that don't depend on each other, as opposed to 9. You could make it go 1,2,3 / 1,3,2 / 2,1,3 etc. And that would allow you to add another 2 custom upgrades -- that way, you could have additional upgrades that didn't require messing around with the game's limits. Could something like this work?
--cittran