NEC ECC: Is a change in people and associated handover period a Defined Cost under NEC Option E

When a resource leaves the project and a new individual is employed is the associated handover period a recoverable cost under an ECC Option E contract? Essentially should the Employer be expected to pay for two people to undertake the same role for a short period of time?

If such cost was included in the Application for payment is there grounds for this to be deemed as Disallowed Cost?