Is AUDIENCE SPLIT DECISION STEP IN THE CAMPAIGN CANVAS a real random split?

Great feature. But I can't find any information if this is a random split.

If not, I would rather stay with the old workaround by filtering for last ID digit.
If yes, it would be great to understand how the randomization is implemented.

Thanks for any feedback.

(I try to asked this question already in https://community.oracle.com/topliners/discussion/4477973/eloqua-tips-split-decision-step-in-the-campaign-canvas and https://community.oracle.com/topliners/discussion/4477806/audience-split-step-in-eloqua but questions did not appear)