Deferred Tax calculation in EOU

Hello Friends,

I have a query. There is pvt. ltd. company which was exempted from Income tax for 5 years. Hence it was subject to MAT during these 5 years. It is coming under regular tax net from April 2011. Do we need to calculate Deferred tax on diffrential depreciation as on 1.4.2011 ? (assuming that if it would not been under MAT and regular provision would have applied then diff between depreciation as per IT Act and Cos. Act for 5 years).

Please advice.

Thank you.