Air infiltration for Windows and compliance with IECC 2018 for European windows

Many deparments of permitting are now requiring compliance with IECC 2018. According to the 2018 International Energy Conservation Code (IECC), the air infiltration requirement for windows is a maximum of 0.3 cubic feet per minute per square foot (cfm/ft²) unless the window is site built. For European windows that are not certified by NFRC, this value is not available so is there a way to still use European windows without NFRC certification in this case?
For U values and SHGC there are tabled standard values that can be use in a Rescheck calculation but I do not think this is the case for air leaks so I do not see a way out from NFRC certification. The problem is that European windows with NFRC certification are a small fraction and are also 15 to 20% more expensive in my experience.
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No one? How can top architets use European windows without NFRC certification in the USA? I have the impression this is one of those "don't ask don't tell" topics. The interesting part is that most Chinese manufacturers provide NFRC certification but there are maybe only a couple of European manufacturers that do so.
That's interesting....I had to look it up to believe it for myself because I didn't recall seeing it. My hope is that Mauro is correct and code enforcement doesn't know, or doesn't ask. Hope someone smarter than me here has an intelligent argument to make for the lack of an NFRC rating.
Well thank you for confirming my concerns. Let's see if anyone with more experience on the field can comment.