No the steem price is irrelevant. As it issues you steem based on the USD equivalent. (Ie 5 STU is 5 steem if steem is $1 and 10 steem if steem is $0.50, and 2.5 steem if steem is $2).
The only market variable that matters with respect to payout is SBD as it assumes it is worth 1$ and issues them accordingly when in reality is it is not a perfect peg an frequently breaks to the upside.
and when SBD is below 1 dollar...?
Well SBD below one dollar in theory is better 100% power up. But SBD normally stays at close to one dollar as you can redeem it for 1$ worth of steem via a blockchain conversion so it keeps a floor. It takes seven days to redeem however to at times like the moment when the markets are moving fast it can fall below a $ .
thanks, i have to correct this post 🙇♂️