The PIA is computed using the rules the number holder is subject to, either NMISSS or Title II.

Title II rules apply unless the beneficiary was previously eligible as an NMISSS survivor beneficiary. Eligibility to a life NMISSS benefit is not considered for this purpose.

NMISSS rules continue to apply to PE events for those subject to the NMISSS rules. Once the PIA is computed under Title II, Title II PE rules apply.

All earnings after 1986 are SSA covered earnings. All recomputations using those earnings are made under Title II rules. If the recomputed PIA is higher, Title II entitlement is effective. A recomputation that is disadvantageous to the NH or other beneficiaries may be waived (RS 00605.407).

When an auxiliary becomes entitled on a NMISSS record on or after 1/1/87 that auxiliary is subject to Title II rules. It is therefore possible that there will be records with some beneficiaries entitled under NMISSS and some under Title II. Each beneficiary is subject to the rules under which they were entitled. However if the PIA changes to Title II, then Title II rules will apply to all beneficiaries.

When an individual becomes subject to Title II rules, those rules are applied as of the first month of the Title II entitlement.

In counting reduction months, adjustments to the reduction factor or delayed retirement credit months, apply Title II rules beginning with the month the beneficiary became subject to Title II rules. The number of reduction months or credits begins with the first month of Title II, not the initial entitlement under NMISSS.

It is possible that a number holder who was entitled prior to 1987 under both NMISSS and SSA may acquire an auxiliary after 1986. That auxiliary will be entitled only under SSA's Title II rules. Benefits for such a dual program auxiliary beneficiary are based on a Title II benefit computed using all NMISSS and SSA earnings. That auxiliary cannot be entitled on both records because anyone entitled after 1986 is limited by the covenant to only SSA benefits.