MAND went up 500kg!
Let's play them at their own game. Every time the ZFW drops, then rather than use the correction, ask for a new plan.
They have a choice, either give me a new plan (time cost), or I take the CFP fuel based on the original weight (fuel cost). Let IOC decide which is their preferred option.
Unlike many things in fuel policy, Depress Fuel at the crit point is not just a planning requirement, and if you leave without it, or more to the point, arrive at the crit point without it, you are operating outside the requirements of the AOC.
OK, the chances of having a depress at or near to the crit point are slim, and the chances of having it happen on the day you've reduced fuel via the correction are even slimmer.
HOWEVER, if your flight file gets selected at random by the CAD in one of their audits, and they conclude that you were operating not in accordance with the AOC, who gets called into the office? (hint: it's not the dispatcher, or load controller or IOC)
Even worse, if you do it going eastward, there have been cases in the past where the authority at the destination (read NavCanada or FAA) has boarded the flight to do a document audit. Once again, who will be held responsible?
Not worth it, give me a new plan, or I take CFP.