How do I price a time and materials contract, given that my overhead
rate is about 90% of the direct cost of a job.  I am doing service
work on commercial and industrial roofing.  Supervisors work on
several jobs each week and it is not possible to charge their time
based upon collecting data from time sheets.  If I show the price per
hour to be too high, I'll lose the bid, for which selection is based
upon hourly rates.  I need to somehow associate the supervisor time
with the crew time on the job and add the supervisor time to the crew
time.  Can you help me with specific answers and back-up reference
material available by download?