Modding population reproduction rate

Im trying to reproduce the SEIV Proportions mod slow populational growth. I changed the following in the settings.txt file:

Race Starting Percent Reproduction := 2
Race Starting Percent Migration := 0
Race Migration Added 1 Percent Per Population Amount := 5000
Reproduction Check Frequency := 10

I understand that these settings should result in just one annual reproduction check and that the base reproduction rate would be 2%. There should be no migration unless it was a planet with more than 5000M population.

When I run the game my homeworld is populated by beings reproducing at 8% each year. I fail to comprehend why.

Any experienced modder's help would be appreciated.