John F,
Being in the hover, into wind (say 10 knots), bang on the markers.
You then decide to turn downwind and, hey presto, you need a bunch of power to remain in the hover because you have just lost 10 knots worth of lift pixies (I think at lower speeds they a called a 'Clatter' of LP's, then a 'Gaggle' until about 600+ knots when they are referred to as a 'Philharmonic'), which is a fact! However, sitting in the hover on the markers, is, by it's very nature, referenced to groundspeed (0) and therefore, we have to make power adjustments to maintain our position on the markers....
Now, if we then take away the earth and we fly 0 IAS and maintain this whilst turning downwind without adjusting power, we will not fall out of the sky......if we then magically make the earth re-appear and look down......we will no longer be on the markers but will, in fact, be moving downwind.....and our net lift-pixies remain the same!
If you agree, then I mis-read your post and apologise! Easy:
Working Groundspeed = Be careful
Working Airspeed = Fill yer boots