One of the biggest confusion of new Steemians is the realization that the $mark beside a post payout is not a straightforward dollar.
Well, actually it's called Stu. Steem Token Unit is the factor you get beside your post. That dollar mark is subdivided into steem power and sbd ie on 50-50. Right now it's even more complex with the added STeem payout (which I like btw).
The calculation is pretty simple. Assuming you are earning $100 here's a breakdown of the payout assuming steem and sbd are both 1$ each. After taking away the 25% for curators.
37.5sbd
37.5 steem power
Now we get payouts in steem it means the system is trying to correct an sbd debt hence is replacing some sbd with steem. So out of the 37.5 sbd we may actually get like 12.5sbd and 25steem.
I shouldn't go into more details to avoid further confusion. One thing I want you to note though, 50-50 payout is is going to mostly be your best bet. The only time 100% power up will do you more value is if steem is less than $1 and also less than sbd. That's a long short so stick to 50-50.