ThreadFlags3 in the KTHREAD

For the 2004 edition of Windows 10, the KTHREAD has a new 32-bit set of bit fields. The ThreadFlags3 itself is a LONG volatile in union with an anonymous structure of ULONG bit fields:

Mask Definition Versions Remarks
ULONG BamQosLevel : 8;
2004 and higher (x86) previously 2 bits in ThreadFlags
ULONG ThreadFlags3Reserved : 8;
2004 and higher (x64)  
ULONG PpmPolicy : 2 ;
2004 and higher previously in ThreadFlags2
ULONG ThreadFlags3Reserved2 : 22;
2004 and higher  

The x64 KTHREAD also had the BamQosLevel as 2 bits in union with ThreadFlags but accommodates the widening to 8 bits by moving it to the union with ThreadFlags2. It is not yet clear what’s intended by this difference of treatment.