Interest on lump sum

[SSRRS]

Hi,

Thank you as always for the insights.

The owner of Corp that sponsored A DB plan (traditional) passed away in July 2024 at age 61 and 8 months. The plans NRA is 62. The plan default (if no election was made) is first to the wife, if no wife, then the distribution goes to the children. 

The wife was entitled to a lump sum in 2024.  However, the election forms etc. were not finalized, not due to beneficiaries fault, until May 2026.

1. Can you calculate the lump sum as of 2024, and then give interest since the lump sum was not paid until 2026.

2.Or must you actuarialy increase the accrued benefit from 2024 until the payout date of 2026, and then calculate the lump sum as of 2026?

3. Or are both methods ok?

Thank you