anchor.diff:  				{_, {struct, ProdPriceObj}} = lists:keyfind("price", 1, Object),
   				ProdAmount = prod_price_price_amount(erlang_term, ProdPriceObj),
   				CurrencyCode = prod_price_price_c_code(erlang_term, ProdPriceObj),
  +				ProdVF = prod_price_vf(erlang_term, Object),
   				RCPeriod = prod_price_rc_period(erlang_term, Object),
   				ProdDescirption = prod_price_description(erlang_term, Object),
  -				ProdValidity = ProdSTime - ProdETime,
  +				ProdValidity = ProdETime - ProdSTime,
   				if
   					ProdValidity =/= {error, format_error} ->
   						{ProdUnits, ProdSize} = prod_price_ufm(erlang_term, Object),
   						Size = product_size(ProdUnits, octets, ProdSize),
   						Price1 = #price{name = ProdName, description = ProdDescirption,
  -							type = ProdPriceType, units = ProdUnits, size = Size,
  +							type = ProdPriceType, units = ProdUnits, size = Size, valid_for = ProdVF,
   							currency = CurrencyCode, period = RCPeriod, validity = ProdValidity,
   							amount = ProdAmount},
   						case lists:keyfind("productOfferPriceAlteration", 1, Object) of
  
positive.code: 			{SDT, EDT};
  		_ ->
  			{error, 400}
  	end.
  
  -spec prod_price_name(Prefix, Price) -> Result
  
negative.code: po_alteration(json, ProdAlter) when is_record(ProdAlter, alteration)->
  	try
  		Name = prod_price_alter_name(json, ProdAlter),
  		ValidFor = prod_price_alter_vf(json, ProdAlter),
  		PriceType = prod_price_alter_price_type(json, ProdAlter),
  		UFM  = prod_price_ufm(json, ProdAlter),
  		Description = prod_price_alter_description(json, ProdAlter),
  