Tell me what to do and I'll do it. Don't scope out 2 weeks worth of work for each member of the team, knowing that since all tasks take longer than expected, each member either has to work 50 to 60 hours a week, or come up with an excuse why the work didn't get done. No change to existing code is trivial. There are always surprises. You end up with 10 people in every meeting justifying why their work took longer than expected. That's causes stress and lowers morale.