Going 50/50 doesn't mean you will get equal amounts of SBD and SP. You will get equivalent values. If you take a closer look at your next reward, or check your wallet history, you will see you are receiving less SP than SBD on those 50/50 payouts. At last these days, when 1 STEEM equals 1.3 to 1.4 SBD.

The values you list in the table is volume, not the unit price. Unfortunately STEEM is not at 10 USD… yet =)

If you expect the STEEM value to drop in the near future, then you would make a profit going 50/50, now and trade the SBD at a low point.