You would need to tell us what your fare class was on the return. That said, although KE excludes lots of discount Y fares from any mileage whatseover, there aren't any fares where where they only offer 25%. Moreover, on all partner airlines, an elite bonus either applies or doesn't, but isn't tinkered with -- i.e., a GM entitled to a status bonus should always get 100%. You can check DL's official list of earning amounts by KE fare here.