@critstopher is right. SDB and STEEM are not fixed price even though they're attempting to peg to the US dollar. Based on the newest update from coin market, your STEEM and SBD price might show higher or lower amount of dollars.
However, the way post payout is distributed is not very transparent. I'm not sure if the post is based on USD and then convert to STEEM and SBD or vice versa. If anybody can answer that, that would be very helpful.
Thank you for the reply...may you and critstopher are right..if anything then..please comment export of the steemit community...I am also new here... Appreciate your answer @critstopher and @sumdumphok