I'm impressed. 14 man days for 3000 plants is fast. That's 200+ plants per day.
I don't know if I could MOVE 10,000 gallons of pot to a site in 3.5 days. And the thought of digging 3000 holes with a one man auger makes my back hurt.
So how much did you charge per plant? Did you provide, or did they? Were they already on site?. What was your soil like? Locations already marked? Any soil treatment needed? Just planting, or weed barrier & mulch too? Multiple species?
Not being critical, just curious.
You can bid on the basis of making it cheap enough to get the contract.
You can persuade people that you know what you are doing, and so they should take the higher price, in terms of higher expected survivability.