I've passed campaign once and want to do on the Brutal now.
After passing all 3 first missions I did the "Smash and Grab" - the 1st artifact missions. Upon completion I've discovered that I don't have laboratory available... Then I did "The Evacuation" - the 1st colonist mission.
I've passed the missions twice: - 1st time on Brutal level. Here I've collected all 3 Zerg artifacts and used one "re-load"; - 2nd time on Hard level to get "Sacrifice Nothing" achievement (Complete "The Evacuation" mission on Hard difficulty without losing or salvaging a structure). Actually I've completed "Handled with Care" achievement too (Complete "The Evacuation" mission on Normal difficulty without losing a Transport Truck). And also I've collected all 3 Zerg artefacts on 2nd pass.
When I've visited the laboratory I've discovered that I have 4 Protoss research points and 6 (!) Zerg points...
Question: What is a source of additional 3 Zerg points? As far as I know, till the end of all researches done no new research points are available when missions are completed.
Am I correct? Or each mission pass gives you all available missions research points?
P.S. Here is a similar question (I missed some research points in some levels, can I replay to get those points?), but it's answer is not clear for me.