Im an insurance broker and have worked in the insurance industry for over 6 years and there’s 2 things to know... 1) insurance is different everywhere as it is rated down to the zip code 2) rates fluctuate each year and each carrier has a different rating system.

Specifically, for me in that market that involves forced appreciation to get a short term equity bump to insulate me to some extent from short term market fluctuations and hold from a position of financial strength (combined with my forced cash flow, down payment equity, cash reserves, and other income).

In the case of land, I would just research similar size lots in the area and find the average sales price in the last 3 months or so (possibly 6 months), considering land values don't fluctuate as much as homes.

I've heard about NFCU rates fluctuating with the market.

Builder pricing fluctuates by location and many other factors.

Like you mentioned as well, costs may fluctuate from month to month, and there's some margin of error that you need to account for.

Market fluctuations do not matter.

I see no reason why the payment structure should fluctuate based on the amount of rent that I am getting for the property.

They have fluctuated for a variety of reasons.

Even within those zip codes things fluctuate.