Referral bonus when flight is split UC/PE?

I've referred someone for FC, the site gives different referral bonuses depending on their first flight (I think it's 5k for PE round trip and 10k for UC). Does any one know what happens if they do a round trip which is PE out and UC return?

You'll get 2,500 miles for O/B and 5,000 for I/B.

Makes sense! Cheers