Meaningful values of Inclusive Duration in C++ Build Insights?

Question

I have used vcperf to analyze the build process of a C++ project in order to see if there're bottlenecks, but the representation of the values is not very insightful.

For instance, the whole Duration is said to be 3,289.218 seconds, which accounts to roughly 54 minutes - the total time it took to build the project (using 14 threads).
But if I look into, for example the files report, I have <chrono> Included Path as a number one with the longest Inclusive Duration (s) Sum as 3,577.424 which doesn't make sense to me. I might assume that it is the sum across all the threads, but I don't find it useful for analysis.
In order to see the impact I need to understand the actual percentage of the total build time, meaning that either Duration has to be calculated in the same manner (spent in all the threads?) or the Inclusive Duration to be calculated as a part of Duration.

Is there a way to get the meaningful values in Windows Performance Analyzer or do I have to use the Build Insights SDK and do some custom calculations?

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I've looked into the TopHeaders example that uses the SDK and they have the following code:

    AnalysisControl OnStopActivity(const EventStack& eventStack) override
    {
        switch (eventStack.Back().EventId())
        {
        case EVENT_ID_FRONT_END_FILE:
            MatchEventStackInMemberFunction(eventStack, this, 
                &TopHeaders::OnStopFile);
            break;

        case EVENT_ID_FRONT_END_PASS:
            // Keep track of the overall front-end aggregated duration.
            // We use this value when determining how significant is
            // a header's total parsing time when compared to the total
            // front-end time.
            frontEndAggregatedDuration_ += eventStack.Back().Duration();
            break;

        default:
            break;
        }

        return AnalysisControl::CONTINUE;
    }

This seems almost useful, since their program shows the actual percentage of time it takes to parse the header: 7% for chrono.
7% of a total duration of 50 minutes is somewhat significant. But it is a percentage of the front end pass. What percentage is front end pass itself? 30? 50? Can't say. Hence, can't know the actual impact...

Now, I think this code can be modified by adding other event ids.