For those of you wondering why $1 worth of burned SPS only mints 975 DEC rather than 1000 - the reason is to provide a small buffer which helps prevent certain potential price manipulation exploits. The same mechanism is used with the conversion process from HIVE to HBD tokens and has worked well so far there
If I remember correctly, the HIVE -> HBD conversion takes 5% as a fee, and the SPS --> DEC conversion will take 2.5% with above explanation.
Anyway, I put my trust in this process and just convert my asset to DEC. If DEC comes to the peg, it will be a 60% profit :)