How much difference does a metal pole make when it's sitting in the middle of all the lower elements of my beautiful new highly optimized to the max YO.EXE 10 m yagi ?

I get it that the the closeness of the pole will mess up the impedance a bit.

But the elements are still there in the right place with the right length constructively adding to a destructively subtracting from the incoming signals (for example) and after a few tests it seems that a metal pole makes less difference that you might think.

Does it just affect the radiation pattern in the elevation plane ? Can anyone tell me if actually a metal pole which only goes up to the boom lowers the angle of radiation ..