Did not complete [A Mask for All Occasions] after 2 events (2 years)

yo,
Its last day of Hallow's End in-game event.
Last year 6 masks left to complete achievement named [A Mask for All Occasions] - https://www.wowhead.com/wotlk/achiev...-all-occasions
This year i pushed myself to camp inkeeper and every hour after debuff fall I do Trick or Threat! Headless Horseman kill and bucket daily quest. My camping was usually from 8AM to 10PM. Only three days where 6PM-10PM due job.

So after my striving 1 mask left. I do not get it how is it even possible does not get this achiev in two years.

This achiev is really bad so question:

Isn't there any better % to get masks which you need on Warmane or something like that?
I know achievement change in Cataclysm where you can buy masks you need.

Thank you for supportive comments
-Jeffx