If one person can inspect 100 machines per year and each inspection brings 5000$ which is 500k per year of revenue. Then I would pay you a lot of money if I knew that they will be able to inspect 115 machines from now.
Let x = number of actual customers right now
Let y = total salary load
Let z = overhead
Let p = profit
price = (p * (y + z)) / x
Good luck.