how the margins come about
Lets say insurance costs 5% of the hull and for arguments sake the hull is worth $750,000. That makes your annual insurance bill $37,500. Now divide that by the 200 hrs the more expensive operator flys each year and you get an insurance cost of $187.50 per hour.
Now assume the cheaper operator flys 700 hrs per year, that equates to $53.60 per hour for insurance.
That equates to a difference in costs to the operators of $134 per hour which can be passed on to the client if the operator wishes (highly recommended if your chasing work). Now lets say the contract is 200 hrs (not uncommon).
If the saving is passed on the client will save $26,800. Dont see how that affects safety, in fact the power line company will probably be flying with an operator who does alot of that kind of work with pilots who are far more current and experienced (based on the company flying 3.5 times as much as the more expensive operator).
This is in no way related to the tender in this topic, Im just trying to show that a cheap hourly rate doesnt necessarily mean that company is skimping on maintenance. there are plenty of other factors that effect the hourly rate which can be reduced by flying more hours (pilots, finance, advertising, premises and so on.
Hope this is helpful