Past Revalued Assets issue

HI All,

Please consider the below Scenario:

Client has reduced all the Assets value @ 10% as a Revaluation by making a JE in GL and not made those changes in FA Module.

After that each period passing adjustment entries to make effect of the above,since not modified values in the FA.

Now after 2 years, client want each and every asset cost should be modified (adjusted) to that affect and depreciation also should be shown all the periods in FA module.

Mean while some of the assets were Fully Reserved,some of them are Retired.

How can I suggest the client to overcome the above typical scenario.