Can the "annuity starting date" ever change for purposes of 417(e) (e.g. if a participant changes the form of his benefits, or if a new benefit form is suddenly offered)? Thoughts? Thanks in advance!

I think there are situations where you could have a 2nd annuity starting date, for example if the benefit is split due to PPA benefit restrictions, but generally once someone makes their election, based on the available options, they don't get a second bite at the apple.

If the plan offered a new payment form, generally it would not be offered to those who already elected a different form of payment. If you gave them a 2nd bite, it would lead to adverse selection issues.

Maybe if you gave an example of your concern, you might get more responses.

Agreed that in general all retirement elections, once they go into pay status, ought to be treated as irrevocable.

Reemployment leading to suspension of benefits for a temporary period may create a new annuity starting date, but that is, pretty much, it.