OK, so in the table it says +/- 1 hour in the left column, and for improvement to take the application of improvement on a BECMG from the end of the applicable change.
So in your example TAF, it is legal to use as a destination with one alternate, or to use as a destination alternate from 1100z.
A) is the bit which states the validity is taken up to the first BECMG.
B) is badly worded, what it's actually saying is that you don't have to apply the wind if it is overridden by a PROB or TEMPO, but the prevailing weather beyond any PROB or TEMPO should be applied up to the first BECMG.
You're taking the word fully in B to mean for the entire time period of the TAF, when actually the whole sentence is saying apply everything apart from the wind if the wind is amended by a BECMG AT, PROB or TEMPO.
Last edited by RTN11; 19th Dec 2017 at 03:35.