it is illegal practice your company is following.No company can do so ,i feel where you are worrking is not a company at all.
it is a one man show of owner and he donot have professionals in his company.
if you are giving two saturdays off does not mean you will not follow law of the land.indutries are working in five days in a week
still they are giving leave as per shop and establishment act.
your empoyees are adopting correct practice because you are illegaly curtailing their rights.you can not deduct two days salary for one day absence.it will be against payment of wages act.if someone will complaint against this company
with labour authorities, your owner will come in problem