Some form of documentary evidence (or a statement by a disinterested party who was
                  aware of the support situation) is desirable in every case. The more usual sources
                  of such evidence are set out in RS 01301.180.
               
               Obtain documentary evidence or a statement by a disinterested party if at least one
                  of the statements in RS 01301.165B.1. and RS 01301.165B.2. (in this section) cannot be obtained or all other parties are deceased.
               
               Document the file with evidence to support all allegations concerning the child's
                  support situation. In the rare instance where you are satisfied that such evidence
                  does not exist, you may rely on allegations only if you are convinced that they constitute
                  reasonable estimates and you have no reason to doubt their accuracy. Use caution in
                  determining one-half support based on such allegations.