Try 750.% for service contractors that can't keep themselves busy most months:
My State Fund has a minimum $1200. per yr. fee for workers Comp. Insurance. If seasonal help can only average 6-hrs a week, 12-weeks per year, even with clerical documented at 50%, the $55.- Mo. min. payroll services w/ SDI, EDD deductions, & EOY tax reporting, it's $2000 yr min.
Average 72 hrs of summer help, sucking $28. per hour in fees + $16.hr helper wages = $44.hr, before mandatory 401k contribution.
My SEP IRA gets $1500 per month for my retirement, which must be matched for employees. So either reduce my contribution, or add $4500 / 72 hrs = $63.hr for helper.
($44.+ $63. = $107 hr. for helper) Buy that helper lunch, or pick up & drop off, and its more like $120. total per hour. / 16.hr wage = 750.%
New clients won't bite over $60.hr + parts for electrical service in my area. So the helper gets $16 in wages, but costs $120 per hr., and the client only pays $60. That's a $60. loss every hour with a helper. No can do with T&M pricing system.
Would need a Flate-Rate or Piece-Work price book, which triples the best T&M rates in my area, and suckers willing to pay that rate.