Where do you live? I am really surprised that the power company would
put 6 houses on the same transformer. Houses must be located pretty
close together.

Maybe that's the problem. I get the impression that many of the
changes in speed in the air turbine are being caused by other people's
usage. I live in upstate NY.

So is it possible for an unbalanced load to cause the voltage at an
outlet to be different from what the power co. measures at the
weatherhead?