this is from DOLE:
Work days may be reduced on account of losses. The reduction in the number of regular working days is resorted to by the employer to prevent serious losses due to causes beyond his control, such as when there is a substantial slump in the demand for his goods or services or when there is lack of raw materials. This is more humane and in keeping with sound business operations than the outright termination of the services or the total closure of the enterprise.
In situations where there is valid reduction of workdays, the employer may deduct the wages and living allowances corresponding the days taken off from the workweek, in the absence of agreement specifically providing that a reduction in the number of workdays will not adversely affect the remuneration of employees. This view is consistent on the principle of “no-work-no-pay”. Furthermore, since the reduction of workdays is resorted to as a cost-saving measure, it would be unfair for the employer to pay the wages and living allowances even on unworked days that were taken off from the regular workweek.