The primaryinsurance slice of .insurance fixes .focal to "false" which would seem to indicate that it is (was?) not used for adjudication of the claim. Inversely, secondaryInsurance fixes .focal to "true". Is this as intended? If so, some explanation of the rationale may be helpful.

Here is the explanation:

The intent of the two slices is to capture the primary payer’s identification on a secondary claim.
A person may be covered by two insurers due to, for example, both husband and wife working. The wife is primary on her insurance and secondary on her husband’s. When processing her claims, Coordination of benefits (COB) is applied. Two claims for the one visit to a physician result; one adjudicated under the primary payer and the second adjudicated under the secondary payer. For example, EOB #1 would provide the primary insurer’s identity; EOB #1 does not call out there is a secondary payer. EOB #2 would provide the secondary payer’s identification (Coverage to be used for adjudication (focal = true) and the primary payer’s identification (Coverage to be used for adjudication (focal = false)