I speak under correction, but I would think the wind correction is to allow for mountain/standing waves. These can be very powerfull - I have had a colleague relate to me an experience going into Cape Town(9000ft Amsl @ 15DME) where he could not maintain the required altitude as he was caught in a down standing wave - pretty scary.
Anyway, I would have thought that the reason to add the extra height to the MSA, but really only applies when surface wind speed start reaching about 20 kts. Maybe one of the met boffins can fill us in on exact requirements.
Regards
4g
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