Charge for incoming letters in bill of costs

I am a trainee solicitor assisting in the preparation of a bill of costs in a contentious matter. My firm’s cost draftsperson tells me that I cannot make a charge for incoming letters in my bill of costs. Is this correct?
 
Yes. The unit charge for letters out will include perusing and considering the relevant letters in and no separate charge should be made for incoming letters (section 4.16(1), Costs Practice Direction relating to Parts 43-48 of the Civil Procedure Rules 1998), although the terms of your retainer may allow recovery of this from your client.