Hello! Sorry for the super late response, this topic went under our radar.
Please see this response to another topic:
Setting the cruise altitude when loading in the world map is one thing - setting it after the flight has started is another. It is not unlikely that the cruise altitude can be set in the same way that MSFS does it internally when you import a flight in the world map, but the ATC does not reliably pick this up if the flight has already been loaded.
Unfortunately, I don’t think that there is much we can do. We have tried several ways, but none is reliable enough to make a good feature. As mentioned in the other topic, we’ll keep this on our watchlist and if an opportunity comes around to make this a thing, we’ll happily consider it!
Kind Regards,
Malte