Letters out are charged as either a standard 6 minute unit or for the time taken (made up of 6 minute units). The time taken is intended to include the time it takes to read incoming letters. Where solicitors include a clause stating they also charge for letters in, they are effectively being paid twice for dealing with the letter in, will almost never recover this cost from the other side and will almost always have to look to the client to pay for this, irrespective of the outcome in the case. They try to get round it by saying there may be a shortfall between the costs the other side have to pay and the costs you have to pay. The truth is, it is almost guaranteed there will be a shortfall.