Question About Landscape Creation with Heightmap

I was trying to understand the landscape system in Ue5. I read the article “Landscape Technical Guide” in official documentation.

Now I am trying to import my own height map to create a landscape. My heightmap resolution is 65x65. So according to my understand, I should have 64x64 quads in 1 component with 1 section. But the import option only shows 63x63 quads.

Does anything I misunderstand?
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Should be alright see that Overall Resolution change it from (64x64) to (65x65) to help make sure the landscape looks as best as it can.

I debuged the source code finally found that Unreal just croped the redundant data to fit its own quad configuration.