Probably just a lack of understanding of something, but why did I only gain 1 factory when I had 2 listed to be in production?

You produced √2 factories.  Since your Factories must be a positive integer, and the current ruleset offers no solutions, I went by the proposed rules in “Proposal:another patch”.

So, I need 4 factories to make 2 factories at once, yes?

No, you need 2 factories to make 2 more factories.

Having 2 Factories gives you 2^2=4 Production.  If you assign all 4 points to Factories, you will produce √4=2 more Factories.

So, I started with 1 factory. I made 1 more. Then I tried to make 2, but I have only 3 in the GNDT.

14/06 21:23 (UTC) - Bucky
  Chivalrybean’s Cash = $40M (was $50M)
(advancing time)

  Chivalrybean’s Factories = 2 (was 1)
(advancing time)

—-

19/06 01:10 (UTC) - Bucky
  Chivalrybean’s Factories = 3 (was 2)
(advancing time)

  Chivalrybean’s Cash = $30M (was $40M)
(advancing time)

I updated my production to 2 factories here: http://blognomic.com/wiki/index.php?title=Inventory&oldid=5260
and time advanced at 19/06 01:10 (UTC) - Bucky.

Am I correct on all this, or am I in error?

You updated your production to 2 points of production toward factories, not 2 factories.  If you wanted to produce 2 factories, you should have put 4 points into it.

The Inventory page tracks “this is where my Production points are going,” not “this is what I want to build, Bucky can figure out how many points it would cost.”

Hrm…. I shall try to re-read the rules then since I am missing something.