Is report of actuary is compulsory for valuation of gratuity as per ind as-19

International accounting standards IAS 19, ASC 715, FRS 17:
Actuarial valuations are also mandated by other accounting standards, such as IFRS (IAS 19) or US GAAP (ASC 715). Indian companies which are subsidiaries of companies registered outside India, will often require actuarial valuations and reporting to be done under either of these international accounting standards. This is required for consolidating their results into that of their parent companies. The requirement to conduct actuarial valuation under these accounting standards is incremental to the requirements of AS 15 or Ind AS 19.

So, Ind AS: 19 not mandate Actuary Valuation, it mandate if inclusion of foreign units, H.O, Branch etc.