I know how it works. I have owned multiple houses (not at the same time, so put down your pitchforks)

I'm just trying to draw a distinction between the home loan part (what you get preapproved to spend) and the rest of the fees you're expected to pay monthly. The home loan part is traditionally a fixed payment, whereas the taxes/insurance can vary over time.

My last home was 860/month for the mortgage to pay principle and interest. Over 6 years the taxes/insurance went from about 300 to 400 a month.