Summary: When both Steem and SBD were valued at $1 per coin, the current rewards calculation made sense. But now that SBD is hovering between $11 and $13 per coin while Steem lags at $2 to $2.50, I think the current rewards calculation needs to be revisited and revised.
Following is the current rewards distribution process, based on my recent rewards redemption:
Every 7 days after posting, Steem rewards are distributed to both the author and the curators. The author is supposed to get 75% of the total rewards value and by default, this amount is split into SBD (50%) and Steem Power (50%). SBD is then converted into Steem Power by dividing the amount by the "average market value" of Steem.
By way of example, assuming your post earned $100 SBD and assuming you selected the default 50% 50% distribution, you would get around 40 SBD or 40% (instead of 75%) as follows:
To clearly see the missing puzzle, allow me to recalculate by converting into Steem and USD:
In other words, the total value of your authorship rewards should be 75 SBD (equivalent to 415 Steem Power or 877.50 USD). Compare this to what we currently get which is 40 SBD [37.50 + (17.77 / 5.54)].
THE question then is, where does the difference of 35 SBD (75 - 40 or around 421 USD) go?
It would be great is Steemit Management look into this since the issue magnifies as the value of SBD increases exponentially while Steem's value lags behind.
If I missed something, I would be glad to know.