Schedule A and "back" commissions

I am preparing a 5500 for a large welfare benefit plan.  The agent has informed me that one of the insurance companies failed to pay them commissions for several years and when this was discovered, they made one large payment of those commissions in 2020.  Would you report the entire amount paid on the 2020 Schedule A even though a majority of the amount reported was actually for other Plan Years?  I don't see anything in the instructions that address "back" commissions. 

Thanks!  

I would report it on the schedule A for 2020. That's when it was paid. To be completely honest, I don't get too worked up over Schedule A's - while others may have a different opinion, I have NEVER, in 36 years in this business, had anything on a Schedule A questioned or investigated. 

The Schedule A form uses the word “paid” 31 times.

It has one mention of “accrual”, only for counting retention charges on an experience-based contract.

And nothing in the Schedule A portion of the Form 5500 Instructions uses the word “accrual” (except to describe a benefit-responsive contract held by an individual-account retirement plan).

Not mentioning a choice of accounting methods for Schedule A might have been a considered choice.  For example, the Schedule C instructions say:  “Either the cash or accrual basis may be used for the recognition of transactions reported on the Schedule C as long as you use one method consistently.”

Thank you both for your comments/responses.  I had recommended to the agent that we report the whole amount for 2020 and that we could add a footnote if that made him feel better about reporting the large amount.  I'm glad to see my recommendation matched your responses