一个微秒级定时循环的问题，想知道误差会出在那一段代码中？

#include <windows.h>
#include <stdio.h>

int main()
{
    long long SleepMSTime = 10000; // 毫秒

    LARGE_INTEGER frquency;
    QueryPerformanceFrequency( &frquency );
   

    LARGE_INTEGER StartCount, DoingCount;
    QueryPerformanceCounter( &StartCount );
    DoingCount = StartCount;
    for( long long Times=0; Times<100; ++Times )
    {
        for( ; QueryPerformanceCounter(&DoingCount), (DoingCount.QuadPart-StartCount.QuadPart)*1000<frquency.QuadPart*SleepMSTime*Times; );

        //Doing();
        //printf( "%lld\n", DoingCount.QuadPart*1000/frquency.QuadPart );
        printf( "%lf\n", (DoingCount.QuadPart-StartCount.QuadPart)*1000.0/frquency.QuadPart );
    }

    return 0;
}