Also, I don't think that more hashpower means more orphaned blocks. Since yesterday the hash power doesn't has increased. As you've already said, hashpower of network is decreasing instead. So your theory might be wrong.
But as you've noted, Dark's pool has more orphaned blocks since yesterday. And (sorry for repeating), I think, that's because Dark's pool owned nearly all hash power in past. But now, that some of its hashpower has migrated to other pools, there is a really hard competition between pools to find next block. Because block time is so short and blockchain sync seems to be too slow, there arise different blocks on same height.
I wonder why it takes 10-20 seconds until a block, that was found by Dark's pool and accepted by blockchain as new top block will appear in my local coin daemon. So my pool often works 10-20 seconds for nothing until it get's notified about new top block. And when block time is 60 seconds, it's plausible that there appear many orphaned blocks.