This is not a desirable result and adds costs. It is important to measure the customer's perception of your ability to provide the correct service based on the customer's immediate needs. The best way to understand if the support options or mix is correct is to ask them. This requires some sort of survey or interviews. If one were to only perform empirical measurements of how often different service delivery methods are utilized by the customer, one would miss the critical measurement of how many customers refuse to use any of the services and go elsewhere.
Caution is recommended when only technologists provide sources of automated support.
Often, the human element is overlooked in favor of the latest and hottest tool. We have all experienced web sites that appear to have no clue as to how a customer will use them effectively. We give up and try elsewhere. Include an optional questionnaire in the web site for people to complete to provide feedback. Have support personnel ask short, quick questions of the callers about their awareness or usefulness of your web site.