With this piece, on the Steem blockchain, it is assumed that SBD maintains the peg of $1 and that would be utilized for the debt ratio.

Thanks for the reply! From the blockchain's perspective, I think the price of SBD is always 1 USD because that's what it has to pay (in STEEM) if people make use of the built in SBD -> STEEM conversion function. I'm pretty sure that it uses $1 in its debt ratio calculation, since that percentage matches what we're seeing with partial payouts right now, but I didn't find the relevant section of code, yet. I might do some more looking again this weekend.