I'm not a software developer so take what I say with a grain of salt.
Valve's GDC 2016 presentation seems to imply that asynchronous timewarp is in-fact supported by the HTC Vive at the API level.
The latest SteamVR changelog also mentions it
Honestly, I'm not sure what the difference is between "Asynchronous Reprojection" and "Interleaved Reprojection Hint". Valve's description of Interleaved Reprojection makes it sound identical to what Oculus has been calling "Asynchronous Timewarp", albeit locked to 45fps and limited to rotation only.
Ultimately, it doesn't matter what we call the method as long as the end result is a smooth and playable experience. I'd be great if someone could try the Vive with DCS World and check. Sims are much much heavier than the "Made for VR" games/demos so even if these are smooth, we can't be sure that DCS World will run great too.