Make a good indirect letter for this scenario:  

You are a manager of a four-person crew with the "Green 2 Go" company.  Recently, you have become concerned about the amount of overtime worked by you and your group.  First, you are worried that excessive overtime might lead to errors by exhausted workers.  The four employees on your crew often work at dangerous sites with poisonous chemical such as herbicides and pesticides.   Mistakes could lead to worker exposure to chemicals or errors in recording data or collecting samples.  Second, three of your four field-workers have complained about their 50 to 55 hour weeks and the excessive time spent out of town on projects.  Although they like the overtime pay, they would prefer to average just an extra five hours a week.  You are concerned that they may quit and start working at a competing firm.  Third, you are convinced that there is enough work to support a fifth field employee, and still have three or four hours of overtime per employee per week.  (Of course, you realize that there is always the risk that a future work slowdown would mean laying off an additional worker.)  Given these concerns, write the letter's body to the branch manager, Joe Tremblay, describing your concerns.  You also want to suggest that Green 2 Go hire another field-worker, or at least give the matter some study.  Present this information to Tremblay using the letter format.