Hiked salary and wages.

I am working with govt of India undertaking. The salary of employees was revised wef from 1.1.97. in the office order for revision there was clause for stagnation increment grant of upto a maximum of three stagnation increments for those who reach the maximum of their scales. Accordingly employees when having reached maximum of the scale were given three increments. The next revision was due from 1.1.2007 which also has now been implemented since Nov 2009. However in the current order for stagnation increment clause is "employees will be paid three stagnation increments , one after every alternate year on raching maximum of the scale. Problem - Based on the basis of basic pay as on 31.12.1996 the salary was revised to new basic on 1.1.2007. We are getting the revised salary since then. Now suddenly management has issued an order with retrospective effect that "the employees have been given stagnation increment every year instead of every alternate year and has issued order for pay fixation to be rectified wef 1/1/1997 - taking into account one increment every alternate year. In the original order there was no clause for stagnation increment every alternate year, it was stated that employees will be given upto maximum of three stagnation increments. Questions Can management issue orders at a later stage, that two when new wage revision has been implemented. Can management decision be challenged in court of law?