c) The diection is also averaged and changes in direction will only be reported if they are 30 degrees from the average.
Thus a wind forecast of 23015 can mean;
Wind direction varies from 200 to 260 and speed varies from 4 to 24 Knots.
I think you're mixing up METARs and TAFs here, DFC.
In a METAR, variations of more than 60 degrees (typically 30 degrees each side of the mean) direction are reported.
In a TAF, there is no forecast of directional variation. VRB is allowed for means above 3 kt only if it is impossible to forecast a single direction, which is usually reserved for temporary conditions in convective activity.
So a forecast of 23015KT gives not even that weak guarantee over direction. The 230 is a mean, but the wind may be traversing 140 to 320 or worse.
All the more reason to fly the weather you find, not the weather that is forecast.