Hurra !! It works ! I increased planet population 10 times (Earth will have 20 billion instead of 2), scaled up population modifiers and decreased pop. mass. Now, SE IV ships 500 (not 300) to a planet than shifts to another ! New 500 is exactly 50 in "unmodded" Proportions. Funny thing happens in Planet with moons. After filling planet, SE ships 500 million people to a moon before going to another planet

. Anyway, it works and works much better than in 1.78 IMHO.
I can post modded data files if you like.