Board Thread:League of Legends discussion/@comment-25532677-20141013050627/@comment-1330314-20141029182809

Some AD champions have AP ratios to accomodate for and the Baron buff, but I don't think this is intended here. Sion has AP ratios on some of his abilities because they're not meant to really scale with items: champions have tightly controlled power curves based around their interaction with items, and changing the ratios here to something Sion could scale properly with would disrupt his power curve and likely cause him to scale too hard. Perhaps here was intended to be a potential pick for Sion (though not a very good one), I think the main reason there's an AP ratio here is because it's better than having no ratio at all.