Highhorse....you say 'steady state' and by that if you also mean inertial effects are not to be considered, then, of course, your arguments are correct. But that's kinda disingenuous.

Because, in the real world, planes/models have mass, and therefore are subject to the laws of physics ...i.e., they cannot accelerate at an infinite rate to immediately match changing conditions....whether gusts or a turn from (say) downwind to upwind. There will be an effect, however small, as the plane/model does, indeed, require some time to 'catch up' to that sea of air around it. That effect may be undetectable during slow turns/maneuvers....perhaps your 'steady state'. But a fast transition (e.g., from upwind to downwind) will produce a loss in altitude (all else being same), as the model must lose lift in not being capable of accelerating instantly to maintain a same relative AS.

I.e., maneuvers (accelerations) even in steady wind conditions do produce an effect. Simple physics, and demonstrable all the time at the field, esp w/ high inertia (heavy) models. And nothing to do w/ AS vs GS, etc.

Ray