so the values of gust will be different when using powersave or not, which makes it hard to compare. The lower sampling rate could perhaps statistically be corrected to match the 3" one.
Actually I just found this. Formula 15) should give the answer.
But after reading the article from KNMI and others sources it is clear that there isn’t a clear answer. Both KNMI and linked article above do mention the 10 minute period for defining gust values.