A DB plan was terminated in summer 2009.

Is it reasonable to apply for dl letter now?

Assets were distributed in 2009 and plan was a one participant plan not covered by PBGC.
Thanks.

Yes.

Just curious, was the plan's normal retirement age under 62, and if so was the plan amended before the termination date to increase the NRA to age 62?

Yes NRA amended to 62.

That's good. As you probably know, the IRS is asking for data to prove any normal retirement age less than 62 was typical for the industry. Having that amendment done eliminates that headache.

If your NRA is under 65, then they are also asking if the plan coordinates the actuarial increase (for working past age 62) with the limits under section 415 (since the 415 limit generally does not get bigger after age 62). It seems like they're asking you to pick which one applies: the plan violates 411, or does it violate 415? So be prepared for that question too.