Having worked in IT for 34 years, I know of one constant. If the date is set in stone, quality becomes irrelevant. If you were that concerned with quality, you would implement when the system works, not when some manager picks a date out of thin air.
This is why I snorted when they established the new “end of November” date. You can’t pinpoint IT problems with fixed dates. When Verizon’s data center goes down again, it’s just another facepalm.