Projects don't go faster by working with lower quality. They don't go slower by demanding higher quality. Higher quality results in faster delivery, particularly as the project matures. Lower quality will result in slower delivery that is less predictable, because it needs more regression testing, more fixes, and the code becomes less agile as it degrades. Every increase in quality leads to increases in other desirable project properties, like productivity, effectiveness, size, stability, re-usability, efficiency, etc. If you have to resolve a job in the current iteration below quality to meet the deadline, resolve to finish the job in the next iteration.