This post seems to be older than 1 year— so keep that in mind while reading. It might be outdated.
For every 100 employees, supervisory costs – including salary and benefits – for city carriers were about $440,000 on average in fiscal 2013, the report (pdf) says.
The supervisory costs of the same number rural carriers came in at about $220,000 on average.
Also, the Postal Service paid about $1.2 million for city carrier overtime, per 100 employees. Overtime for rural carriers was only $236,000 per 100 employees.
The IG says supervisors have more activities to manage for city carriers compared to rural carriers, such as managing
daily workhours and work load activity.