Importance of Communications Planning.
The requirements and functional specs cannot document 100% of the details which are required for the development team to produce a system. It only serves as a guide and a framework for understanding the details that are to fleshed-in during construction phase.
During construction phase itself, the team will need to meet regularly to validate their understanding of what is documented in the specifications and to highly feasibility issues which cannot be foreseen when scoping the requirements.
This meeting can be very informal, esp in a small team. However, it is a required activity to minimise misunderstandings between project members. As the team size increase, a more formal approach to managing communications between members has to be adopted.
Project managers should take note that as the number of team members increases, a communication plan should be used to explain how information should flow between team members, their information needs and who are the decision-making bodies for each type of decision to be made. This will set expectations and prevent fragmentation of information which leads to misunderstandings.