Detection of gusty wind group for change fails

[maartenlterpstra]

A change in wind is only allowed if the change in wind direction is greater than 30 degrees or change in wind speed is greater than 5 knots. EXCEPT when it becomes gusty.
E.g. 07012 -> 08015G25 is a valid change because it becomes gusty even though the other change criteria are not met.

This ought to be valid.