Dear Asfar Paper P5 is Advanced Performance Management focuses on Planning and control aspects of Management accounting like Budgeting, Variances, Costing Modules, Applications of Performance Management etc...
Wheareas paper P4 is Advanced Financial Management focuses primarily on Investment Appriasal, Working Capital Management, Sources of Finance, Capital Structure and it's theories, Risk Management, Porfolio Management, Business Valuation this paper P4 is more advanced Version of previous Paper 3.7(Strategic Financial Management)...Because some of the topics of 3.7 are now transferred to paper F9(Financial Management-Fundamental Module of ACCA) like CAPM(Capital Asset Pricing Model), Capital Struture, Business Valuation, Foriegn Exchange Risks, Interest Rate Risks so these topics are removed from 3.7 and some more complex topics are now included in AFM(Advanced Financial Management)...
Choosing P4 or P5 solely depends upon your 2.4 session because previous 2.4(Financial Management and Control) contained both Financial Management and Performance Management Aspects, so all depends on what your views are about Financial Management topics like Investment Appriasal and Working Capital Management....
If you feel you have good insight in Financial Management Aspects rather than Performance Management Aspects then you should have to choose P4 otherwise, P5...