[TheCapn]

Can I ask what you drive?

There's a 3rd cost that you're sorta glossing over. The work you're doing (and the speed you're capable of doing it in) means you've had a non-negligible amount of experience. Depending on how fickle we're going to get, there's 4th costs of the tools you own allowing you to do that work. Perhaps other costs for your living situation allowing you to have a place to do such tasks.

I do my own maintenance work too. But I think it's foolish to gloss over those aspects of the work. They don't come for free.