No weather update for height option

I wasn't really sure which forum to post this in since they all seem to be for bugs. This is just a question:

Also, I'm using this in X-plane

Regarding the option "No weather update for height". Does this only apply to upper level winds? If I descend to my destination airport will the local metar be applied to the sim? Or perhaps it would have been applied prior to descending through 5000? (depending on how far I am?) Is this option really necessary in X-plane? Can I just disable it? Does this option relate to the 'Transition level" option on the server side? Do I need to change it there to?