Dear Mr. Siow,
First of all, when the company requested employees to agree to the shutdown, it was done on a company-wide basis. Everyone co-operated. Moreover, the shutdown (4 day in a month) is without dateline. Therefore, all leaves will be exhausted eventually and resulted in unpaid leave that will reduce take home pay.
It is totally not fair to those who had agreed in the first place. In the name of " in the best interest of the company" , I believe company can just simply penalise other department that have to take annual leave which they are not supposed to if not of the shutdown. I would think that there is no equal treatment of employees under this circumstances.
Those who have to take leave will be demoralised because of the inequality in the treatment by using "in the best interest of the company" as an excuse. it is in the best interest of the company but not in the best interest of the affected employees. Agree?