Gaps can be a variety of different types and categories. For example, a standard solution might support a business process that the customer does in a different way. Or a customer specific process might be not supported at all. Or some screens need to be modified, for example, by the addition of a few more fields. Or some reports might need to be customised.
If gaps are considered inevitable, Weigandt Consulting will prepare a plan, together with detailed documentation and a description of how to fill them. To avoid as much modification of the standard solution as possible, in some cases it may be advisable to develop extensions.