I don't believe that there is anyone in the pool who has exceeded 12 months as of yet. I think the maximum is 9 months, so if anything it may suggest that BA are not anticipating any course dates for the next 3 months +
The last time the hold pool was extended to 18 months, the world was having a wide awake call from one of the worst known global recessions to be experienced in the majority of our lifetimes. BA were soon to post one of their worst recorded set of financial results and were in a position of near meltdown. The company was receding.
Now, as part of IAG, the company is showing positive growth. Now, I'll be first to admitt, the global situation shows it's new set of challenges and really could go either way. However I believe circumstances are largely different than 2008.