[PS4] Triplets

Hello,

Does anyone know, by any chance, how to increase chances of getting triplets on a console version (without cheat codes and DLCs, just a base game)? It seems more difficult to give birth to three babies on PS4 than on PC. Like, is there any information on RNG (for exmaple, 80% chance of getting single, 15% - twins and 5% - triplets)? 

Have Fertile trait on both parents but it doesn't help much, even after more than 20 births, I got singles and probably just couple twins. On PC version even when just 1 of my sim parents had a Fertile trait, this statistics was more fruitful.

Thanks in advance.