It's a little confusing because your post value is calculated in steem and then displayed as usd value but then payed out in steem and sbd. So if Sbd are worth $1 like they should, the value would be the usd value. But because sbd are trading high on the market, it shows you the value it would be if Sbd were worth $1. But since it's not, the value it displays is actually less when you calculate the price of sbd. So I guess you could say that the steem half is valued in usd and the sbd half is valued in sbd. Normally it's not a problem because sbd should be worth $1. Hopefully I didn't just make that more confusing... haha.