MidAmerican Highland Wind Project tax valuations

I've been seeing a pattern with MidAmerican's  county wind property tax filings. The utility seems to be consistently reporting lower valuations to county assessors, than than the wind project costs that MEC reports to FERC. North American Wind Power featured the utility's Highland wind project in April 2016. The article interviewed the O'Brien county assessor Lowell Dykstra, who reported a valuation of $820,195,459.00 for the wind project.

And, once again, the utility reported a higher valuation to FERC. $822,632,795, or $2,437,337 higher than the county.

 
So, where exactly is the missing $2.4 Million?  Has it been omitted, or reported under the Iowa Utility Replacement Tax at a more favorable rate? Or some other scenario?  $2.4 million missing or possibly incorrectly included in a different tax structure over the 20 plus year lifespan of the project will add up to significant missing revenue for state and local government. Additional information from from state and local property tax officials, and the utility are welcome here.

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