U-Value for Simple Glazing in OpenStudio Results

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Thank you. I am wondering then how the U-value from the OpenStudio Results report can be used to prove to USGBC/LEED that the window has indeed the U-1.22 it is supposed to have. I'd have to tell them that yes, it is entered as U-1.22, but due to internal calculations, EnergyPlus actually uses a different number?

No, you'll have to find the detailed inputs for the actual window construction you're representing and build up a layer by layer detailed window assembly. So, assuming your getting the summary metrics from some window manafacturer, you just need to ask them for what the actual glass emittance/transmittance, conductivity etc. are. Then the calculated U-Value should match your target.

I must admit I am confused. Are you referring to executing all the steps in the Simple Window documentation link you sent earlier? I can only see Step 1 effecting a re-computation of the U-Value, from U-value given (e.g. U-1.22) to glass resistance Rlw = 1/U - Riw - Row, which in turn may become its own U-value, namely Ulw = 1/Rlw? Or are you referring to using something like LBNL's WINDOW?

I apologize, yes you're right. I thought there was a regression being done at some point but I must be confusing this with something. I think Denis has the right answer below.