Additional depreciation

WETHER ADDITIONAL DEPRECIATION IS allowed to power generation units which follows SLM basis of depreciation? Actually as per VK Singhania sir, only those units are eligible for additional dep which follow WDV method, But I have another book by Nitin Jhaveri, which says power generating units can claim additional dep irrespective of method of dep followed, whether WDV or SLM. KINDLY clarify the same.