I have googled all day for this. No luck.
Before someone accuses me of not looking or RTFMing, I have. All I find are links to outdated versions of the software and even then no answer.
So, I have 4 colonies. Each one produces 10 raw production. I'm set to spend all of that production on ships/social projects. Then I set the ship/social meter to 50/50. I've noticed each planet then gets 5 production for social projects even if there is no ship building going on. What happens to the other 5 units? It *seems* like they are wasted. Is that true?