The "Sum SBD" is being calculated as done in the steem system with 1 SBD = 1 USD and by using the median STEEM price. It is only there to show an equivalent to the "Sum STEEM" in a different valuta.
In the coming days I will change the default currency for the sum on the right to USD. The calculation for the SBD may also be changed, so that it shows the amount with using real (external) market values. Since the SBD seems to take a longer flight and maybe go even higher in the next time, it would be better to calculate it in a way we all understand it :)
So the answer to your question is "no", not really... It also contains the earned SP for curation and author rewards.
So its more like gross value rather than net?
With the current settings ( 1 SBD = 1 USD ) it's more like a calculated USD value with ( Sum SP * Median Price ), but as I've mentioned, I'm currently working on a better way to display it with external market prices, so that the amounts of SP and SBD will be summed up separately and multiplied by the external STEEM/SBD prices (CoinMarketCap).
Thanks for all the work!